Add expanded alt text for relevant images (Qiskit#627)

Closes Qiskit#626

---------

Co-authored-by: abbycross <across@us.ibm.com>

docs/run/advanced-runtime-options.mdx

@@ -8,7 +8,7 @@ description: Specify options when building with Qiskit runtime primitives
 
 When calling the primitives, you can pass in options by using the `Options` class or when using the `run` method. In the `Options` class, commonly used options, such as `resilience_level`, are at the first level. Other options are grouped into different categories:
 
-![options](/images/build/options.png)
+![The image shows the top-level options categories: transpilation, resilience, execution, environment, and simulation.](/images/build/options.png "Option categories")
 
 <Admonition type="info" title="Attention">
     This section focuses on Qiskit Runtime primitive [Options](../api/qiskit-ibm-runtime/qiskit_ibm_runtime.options.Options) (imported from `qiskit_ibm_runtime`). While most of the `primitives` interface is common across implementations, most `Options` are not. Consult the

docs/run/configure-error-mitigation.mdx

@@ -107,7 +107,7 @@ stage). This approach tends to reduce errors in expectation values, but
 is not guaranteed to produce an unbiased result.
 
 
-![Illustration of the ZNE method](/images/optimize/resiliance-2.png "Illustration of the ZNE method")
+![This image shows a graph.  The x-axis is labeled Noise amplification factor.  The y-axis is labeled Expectation value.  An upward sloping line is labeled Mitigated value.  Points near the line are noise-amplified values.  There is a horizontal line just above the X-axis labeled Exact value. ](/images/optimize/resiliance-2.png "Illustration of the ZNE method")
 
 The overhead of this method scales with the number of noise factors. The
 default settings sample the expectation value at three noise factors,
@@ -140,11 +140,11 @@ gates. Then it learns the noise model associated with each unique
 2-qubit gate layer.
 
 <figure>
-<img src="/images/optimize/stratified.png" alt="/images/optimize/stratified.png" />
+<img src="/images/optimize/stratified.png" alt="Stratified circuit illustration. There are arbitrary single-qubit gates between each `layer`. Each layer is defined by a block that crosses multiple qubit wires." />
 <figcaption>This is an example of a <span
 class="title-ref">stratified</span> circuit, where the layers of
 two-qubit gates are labeled layer 1 through n. Note that each <span
-class="math inline"><em>U</em><sub><em>l</em></sub></span> is composed
+class="math inline"><em>U</em><sub><em>n</em></sub></span> is composed
 of two-qubit gates on the native connectivity graph of the quantum
 processor. The open boxes represent arbitrary single-qubit
 gates.</figcaption>
@@ -195,7 +195,7 @@ to scale the number of samples accordingly. The following plot
 illustrates the relationship between estimator error and number of
 circuit samples for different total sampling overheads.
 
-![](/images/optimize/sampling-overhead.png)
+![This image shows that the error decreases as the number of samples increases.  The accuracy is best with a high sampling overhead (1000) and worst with a low sampling overhead (1.1).](/images/optimize/sampling-overhead.png)
 
 Note that the number of samples required to deliver a desired accuracy
 is not known before the primitive query because the mitigation scaling
@@ -251,7 +251,7 @@ strings can be much smaller than the dimensionality of the full
 multi-qubit Hilbert space, the resulting linear system of equations is
 nominally much easier to solve.
 
-![Illustration of the M3 method](/images/optimize/m3.png)
+![Illustration of the M3 method.](/images/optimize/m3.png "M3 method")
 
 </details>
 

docs/run/fair-share-queue.mdx

@@ -24,15 +24,15 @@ When you submit a job to a quantum system, it enters the scheduler for the speci
 
 A hub’s entitlement determines its proportional share of the IBM Quantum Premium Plan computational capacity. IBM Quantum assigns shares to hubs. Hub administrators then decide what portion of these shares to assign to each of their groups. Similarly, group administrators will decide what portion of shares to assign to each of their projects.
 
-![Administrator user interface.](/images/migration/admin-UI1.png)
+![Screenshot of the Administrator user interface.](/images/migration/admin-UI1.png "Administrator user interface")
 
 Hub administration user interface. This is used to assign shares to groups. The entire hub share pool is distributed to the underlying groups, and the hub administrator can control the percent distribution by specifying a share value for each group. In this example, Group 5 receives 2 shares of their hub share pool, over a total of 5 shares across all groups. That means that Group 5 receives 40% of the shares pool that the hub was granted.
 
 The fair-share algorithm takes into consideration how these shares are distributed across groups and projects to determine job prioritization.
 
-The scheduling algorithm combines a group’s shares with the shares of its hub, to determine the total fraction of computational power allocated to that group.
+The scheduling algorithm combines a group’s shares with the shares of its hub, to determine the total fraction of computational power allocated to that group. For example, assume you have set up the following allocations: 
 
-![Illustration of how allocation is computed.](/images/migration/allocation.png)
+![Two hubs are shown: A, and B.  Hub A has allocated 20% to Group A and 40% to group B.  Hub B has allocated 30% to group C and 10% to group D.](/images/migration/allocation.png "Allocation example")
 
 To compute the 60% for Hub-A, start with the 3 shares of Hub-A and divide between all the shares at the hub level (3 + 2 = 5 shares in total). This results in 3/5 = 0.6 = 60%. When computing the fraction per group, repeat the calculation inside each hub; the fractions for Group-A and Group-B would therefore be 33% and 67%, then apply these percentages to the Hub-A fraction, which results in 20% and 40%.
 
@@ -42,13 +42,13 @@ The fair-share scheduling algorithm select jobs to execute on a quantum system i
 
 In the following example, we have seven instances arranged between two different hubs. As jobs flow through the system, each group and project consumes some fraction of its effective allotted share. The first image below describes the state at time t1. In between brackets we report the consumption as a fraction of the allotted shares. The fair-share algorithm first identifies the group with the smallest number in between brackets, then the project with the least number in the brackets, and finally it selects the oldest job submitted by that project.
 
-![Fair-share queue example.](/images/migration/fairshare3.png)
+![This image shows how a job might flow through the queue. It shows Group A from Hub A being selected because it has (0.0), then Project B, which is part of Group A is selected because it also has (0.0), then the first job for that project is run. ](/images/migration/fairshare3.png "Fair-share queue example")
 
 A snapshot view of consumption (in brackets) relative to the assigned shares. This scenario has seven different H/G/Ps arranged into hubs, groups, and projects. The next selected group and or project is the one with the smallest consumed fraction of the assigned shares. In this example, the Hub-A/Group-1/Project-Y is selected, and the oldest job (first submitted) in the project is executed.
 
 When the system is ready for an additional job, it repeats the selection. In the following image we represent the state of the queue at time t2. Notice that Group A and Project B consumption were updated to account for the previous consumption accrued between t1 and t2.
 
-![Fair-share queue example two.](/images/migration/fairshare4.png)
+![This image shows how a job might flow through the queue. It shows Group D from Hub D being selected because it has (0.1), which is now the smallest value for the groups, then Project F, which is part of Group D is selected because it has (0.0), then the first job for that project is run.](/images/migration/fairshare4.png "Fair-share queue example 2")
 
 Recomputed fair-share priorities reflecting the previous job execution. A new H/G/P (Hub-B/Group-2/Project-N) is selected based on these updated values.
 

docs/run/instances.mdx

@@ -10,15 +10,15 @@ Access to IBM Quantum Platform services is controlled by the **instances** (prev
   IBM Cloud instances are different from IBM Quantum Platform instances.  IBM Cloud does not use the hub/group/project structure for user management. This section describes instances in IBM Quantum Platform. To view and create IBM Cloud instances, visit the [IBM Cloud Quantum Instances page](https://cloud.ibm.com/quantum/instances). Click the name of an instance to see details such as your CRN for that instance, what compute resources (programs, systems, and simulators) are available to you by using that instance, and what jobs you have run on that instance. 
 </Admonition>
 
-![../../../\_images/providers1.jpg](/images/migration/providers1.jpg)
+![Alice, Bob, and Charlie are all in Hub A.  Hub A has Group 1 and 2.  Alice and Bob are in Group 1.  Charlie is in Group 2.  Group 1 has Project X and Y.  Alice is in both projects.  Bob is only in project X.  Group 2 has Project Z.  Charlie is in project Z.  Therefore, Charlie's instance is Hub-A/Group-2/Project-Z.](/images/run/providers1.jpg "Hub / group / project hierarchy")
 
 The hub/group/project hierarchy that makes up an IBM Quantum instance.
 
 Users with a public account automatically belong to the ibm-q/open/main [open plan](#open-plan). For organizations outside of IBM, designated hub or group administrators assign users to instances. 
 
 To see the instances to which you have access, look at the bottom of your [Account page](https://quantum.ibm.com/account).
 
-![../../../\_images/find-providers1.png](/images/migration/find-providers1.png)
+![Screenshot of the Account page.](/images/run/find-providers1.png "Instances on the Account page")
 
 ## Find your instances
 
@@ -97,7 +97,7 @@ If you do not specify an instance, the code will select one in the following ord
 
 To leave an instance, visit the instance list on your [Account page.](https://quantum.ibm.com/account) Select the instance you wish to leave, then select the overflow menu and choose *Leave instance*.
 
-![../../../\_images/leaving1.png](/images/migration/leaving1.png)
+![Screenshot of the Account page.](/images/run/leaving1.png "Leave instance")
 
 ## Next steps
 

docs/run/processor-types.mdx

@@ -8,9 +8,7 @@ description: Information on IBM Quantum hardware and features of different proce
 
 Processor types are named for the general technology qualities that go into builds, consisting of the family and revision. Family (e.g., Falcon) refers to the size and scale of circuits possible on the chip. This is primarily determined by the number of qubits and the connectivity graph. Revisions (e.g., r1) are design variants within a given family, often leading to performance improvements or tradeoffs. Segments are comprised of chip sub-sections, and are defined within a given family. For instance, segment H of a Falcon consists of seven qubits arranged as seen in the illustration below. Segment H on a Hummingbird, if implemented, could be entirely different.
 
-![../../../\_images/seg-h.png](/images/migration/seg-h.png)
-
-Illustration of segment H on a Falcon processor.
+![Illustration of segment H on a Falcon processor.](/images/run/processor-types/seg-h.png "Illustration of segment H on a Falcon processor")
 
 
 ## Heron
@@ -25,15 +23,15 @@ At 133 qubits, Heron is an [Eagle](#eagle)-sized upgrade to [Egret](#egret) that
 
 ## Osprey
 
-![Osprey processor icon](/images/migration/osprey.svg)
+![Osprey processor icon](/images/run/processor-types/osprey.svg)
 
 Osprey is nearly quadruple the size of Eagle at 433 qubits. The larger chip sizes have required further enhancements to device packaging, as well as custom flex cabling in the cryostat to fit the greater I/O requirements within the same wiring footprint.
 
 *   [View available Osprey systems](https://quantum.ibm.com/services/resources?tab=systems&type=Osprey)
 
 ## Eagle
 
-![Eagle processor icon](/images/migration/eagle.svg)
+![Eagle processor icon](/images/run/processor-types/eagle.svg)
 
 Quantum volume: 128
 
@@ -51,7 +49,7 @@ See [this blog post](https://research.ibm.com/blog/127-qubit-quantum-processor-e
 
 ## Hummingbird
 
-![Hummingbird processor icon](/images/migration/hummingbird.svg)
+![Hummingbird processor icon](/images/run/processor-types/hummingbird.svg)
 
 Quantum volume: 128
 
@@ -69,7 +67,7 @@ Using a heavy-hexagonal qubit layout, the Hummingbird family allows up to 65 qub
 
 ## Egret
 
-![Egret processor icon](/images/migration/egret.svg)
+![Egret processor icon](/images/run/processor-types/egret.svg)
 
 Quantum volume: 512
 
@@ -83,7 +81,7 @@ Egret brings the innovations of tunable couplers onto a 33-qubit platform, resul
 
 ## Falcon
 
-![Falcon processor icon](/images/migration/falcon.svg)
+![Falcon processor icon](/images/run/processor-types/falcon.svg)
 
 Quantum volume: 128 
 
@@ -105,7 +103,7 @@ The Falcon family of devices offers a valuable platform for medium-scale circuit
 
 ## Canary
 
-![Canary processor icon](/images/migration/canary.svg)
+![Canary processor icon](/images/run/processor-types/canary.svg)
 
 The Canary family comprises small designs containing anywhere from 5 to 16 qubits. It uses an optimized 2D lattice.  That is, all of the qubits and readout resonators are on the same layer.
 *   [View available Canary systems](https://quantum.ibm.com/services/resources?tab=systems&type=Canary)

docs/run/reserve-system-time.mdx

@@ -12,7 +12,7 @@ description: Reserve time on a system as an IBM Quantum Network member
 
 Under standard operating conditions, IBM Quantum systems accept jobs according to the dynamic priority assigned by the [fair-share queuing system](fair-share-queue).
 
-![Normal device queuing operation.](/images/migration/normal_queue_with_providers1.jpg)
+![A job enters the queue and joins other jobs from various instances.  The job that entered the queue first exits the queue and is sent to a backend.](/images/run/normal_queue_with_providers1.jpg "Normal device-queuing operation")
 
 While this system attempts to balance workloads for the benefit of all users, there are often use cases where you may require limited-time access at a higher priority level. IBM Quantum provides an option to gain elevated access to specific systems over a specified period of time: **Dedicated mode**. Depending on your hub configuration, if you are a hub admin or group admin, you can reserve time in advance on a particular system with the **Systems Reservations** tool.
 
@@ -29,13 +29,11 @@ Example use cases for dedicated mode include the following:
 
 If you need sole access to a specific quantum system for a given instance, select dedicated mode when making a reservation (only available to members of the [IBM Quantum Network](https://www.ibm.com/quantum/network)).
 
-![Dedicated mode with dedicated jobs.](/images/migration/dedicated_queue1.jpg)
-
-Instance #2 in dedicated mode.
+![A job enters the queue and joins other jobs from various instances.  The jobs that are sent from Instance 2 are all processed in their own dedicated queue while jobs from other instances wait in the normal queue.](/images/migration/dedicated_queue1.jpg "Instance #2 in dedicated mode")
 
 The standard fair-share queue is always blocked when the device is in dedicated mode.
 
-![Dedicated mode with no dedicated jobs leaves the device idle.](/images/migration/dedicated_queue_no_jobs1.jpg)
+![A job enters the queue and joins other jobs from various instances.  There are no jobs from Instance 2.  Because the backend is in dedicated mode for instance 2, no jobs are processed. All jobs wait in the normal queue.](/images/migration/dedicated_queue_no_jobs1.jpg "Dedicated mode with no dedicated jobs")
 
 Dedicated mode with no dedicated jobs from instance #2 leaves the device idle.
 

docs/run/retired-systems.mdx

@@ -6,7 +6,7 @@ description: A list of IBM Quantum systems that are now retired
 
 # Retired systems
 
-The following systems have been retired. For the full list of available systems, see the [Compute resources page.](https://quantum.ibm.com/services/resources?services=systems) By default, the information is shown in the card view, but you can use the view switchers (![view-switcher](/images/migration/view-switcher1.png)) at the top right to change to a sortable table view.
+The following systems have been retired. For the full list of available systems, see the [Compute resources page.](https://quantum.ibm.com/services/resources?services=systems) By default, the information is shown in the card view, but you can use the view switchers (![view-switcher icon](/images/run/view-switcher1.png)) at the top right to change to a sortable table view.
 
 <Admonition type="note">
     To retrieve jobs from a retired system, see [these instructions.](#retrieve)

docs/run/run-jobs-batch.mdx

@@ -15,7 +15,7 @@ Batch mode can shorten processing time if all jobs can be provided at the outset
     When batching, jobs are not guaranteed to run in the order they are submitted.
 </Admonition>
 
-![Batch execution diagram.](/images/run/batch.png 'Figure 1: Batch execution')
+![This diagram illustrates jobs submitted in a batch.  It shows five jobs, numbered 0 through 4, in a queue. The jobs are a mix of Estimator and Sampler.](/images/run/batch.png 'Figure 1: Batch execution')
 
 The following example shows how you can divide up a long list of circuits into multiple jobs and run them as a batch to take advantage of the parallel processing.
 

docs/run/system-information.mdx

@@ -79,19 +79,21 @@ To access the details page, click the name of the system on the **Compute resour
 
 View system configuration values by selecting a system on the [Compute resources page.](https://quantum.ibm.com/services/resources?services=systems) The three tabs in the Calibration data section let you choose how to view the calibration data; the Map view tab is automatically selected.
 
-![An expanded card for a sample system.](/images/migration/exp-card.png)
+### Expanded card for a sample system 
 
-An expanded card for a sample system.
+![An expanded card for a sample system.](/images/run/exp-card.png 'Expanded card for a sample system')
+
+### System tabs
 
 Click the download icon in the upper right of any tab to download a CSV file of calibration data.
 
-![The graph view tab.](/images/migration/graph-view1.png)
+**Graph view tab.**
 
-The Graph view tab.
+![The graph view tab shows the calibration data as a graph.](/images/run/graph-view1.png 'Graph view tab')
 
-![The table view tab.](/images/migration/table-view.png)
+**Table view tab**
 
-The Table view tab.
+![The table view tab shows the calibration information as numerical data.](/images/run/table-view.png 'Table view tab')
 
 
 ## Find system information from other channels