I've got a very long image (200x20000 px) and I need to cut out many rectangular parts inside it (whole width, but setting height of the cutted parts manually) merging edges together. I.e. something like "Crop", but selected part must gone and height of the image canvas must became smaller (it's like I want to throw out some paragraphs in book, which is in one PNG file). What is the most comfortable way to do this? I can use Gimp, Photoshop, ImageMagick etc. Maybe fill this areas with some color and then somehow process it with IM?
- Create horizontal guides where you want cuts to happen
Layer>Guillotine: this splits your original layer into individual layers by cutting it on the guides you have set up.
- Delete the layers you want to remove, as well as the bottom layer (your original layer)
Image>Arrange Layer>Space>Verticallyand use a spacing of 0
Image>Fit canvas to layers