BUG: Image format (.png) is occasionally written twice (.png.png)

[KirilStrezikozin]

This bug report is:

• not a duplicate
• fixed

Describe the bug
Originally reported by: Max Bern (Telegram)
Occasionally image format value gets written twice in the image name:

To Reproduce
Steps to reproduce the behavior:
Unknown.

Desktop (please complete the following information):

• OS Linux
• BakeMaster 2.0

Additional context
Not sure if it's a connected issue, but blender crashes with the setup of Albedo, Roughness, Normal, AO after finishing baking AO and puts .png.png into map's name.

[KirilStrezikozin]

Blender crash is unreproducible, even if I get the .blend file it happened in. I need to resolve image format doubling.

• Find where the image format value gets written more than once

[KirilStrezikozin]

another report:

1st bake - Dorms_ROUGH.png, 2nd bake - Dorms_ROUGH.002.png.png
why 002 if had to be 001?

[KirilStrezikozin]

internal=False, overwrite=False:
1st bake - ok
2nd bake - 002 instead of 001
3rd bake - 004 instead of 002

[KirilStrezikozin]

internal bakes cause no errors

[KirilStrezikozin]

external bake + overwrite gives no errors

[KirilStrezikozin]

• fix image name index doubling (002 instead of 001, 004 instead of 002)

[KirilStrezikozin]

should be fixed by https://github.com/KirilStrezikozin/BakeMaster-Blender-Addon-Dev/commit/b81b2c03f5f960ec98e9b563a1e18c933e3ee9ec