Is there any tool or script to generate custom resolution interface image?

I want to add 3 resolution for VCMI resolution mod (960 x 600, 1067 x 600 and 1200 x 600 ), but have trouble with the interface pcx image. Is there any automatic tool or script to generate it ? If photoshop is the only tool to do this job, I will spent a lot time and make it ugly. :joy:

I guess only Photoshop or Gimp :frowning:

Do you know how HD Launcher did this work?