https://en.wikipedia.org/wiki/Perspective_distortion_(photography) https://de.wikipedia.org/wiki/Stürzende_Linien – in German: “Stürzende Linien” https://learning.oreilly.com/library/view/the-book-of/9781457172410/ch16s02.html#perspective_tool – how to deal with perspective distortion using GIMP – from the “Book of GIMP” GIMP: Tools > Transform Tools > Perspective – it has a shortcut (⇧P), and also an icon in THE Toolbox https://en.wikipedia.org/wiki/Photoshopping
https://learning.oreilly.com/library/view/the-book-of/9781457172410/ Whether you’re just getting started with GIMP or working to master GIMP’s more complex features, you’ll find the answers you’re looking for in The Book of GIMP.
GIMP 2.8 for Photographers: Image editing is a crucial element in the photographic workflow. Image editing tools, most notably Photoshop, are usually sophisticated and deep applications, and are fairly expensive. The only open source tool in this market is the GIMP, which has developed into a powerful, multiplatform system running on Linux, Mac OS X,… Continue reading O’Reilly Media book: GIMP 2.8 for Photographers
I like reusing profile pictures from the web in my Google Mail Contacts aka address book. On Xing or LinkedIn these pictures not necessarily are square, but on Google Mail Contacts you have to choose a sub-square. So maybe you want to resize the picture appropriately, so you don’t cut it, where you don’t want… Continue reading how to make a rectangle image a square image using GIMP