[feature request] preset with exact dimension or smaller

[fily1212]

Hi! Thank you for your project. It is nice.
I'd like to suggest a feature: the possibility to specify the maximum dimension of the images.
For instance I could have 10 images, some of them big and other small. It would be nice to put a threshold of the maximum dimension (x or y) and resize only the bigger one. The 25 - 50% option affects all the images, also the small ones.

Thank you!

[Tichau]

I've added to 720p and to 1080p preset in the default configuration, you can modify these preset to the resolution you prefer.