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Method to batch resize photos with options

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linux-howto

http://www.linuxquestions.org – Hi, I've been using GNU/Linux for many years, and am finally taking steps to reduce Windows to a gaming platform only. One important category is photography. I've used the GIMP a lot and have been quietly browsing several photo apps for various tasks; they've really progressed in recent years. There is almost too much choice! On Windows I used XnView as my image viewer and for simple manipulations, but for batch JPG resizing I found Irfanview hard to beat. It has an intuitive interface for options, of which the following have become musts: resize longest side, maintaining aspect ratio specify the exact number of pixels select a useful algorithm (usually cubic) set JPG compression process subdirectories recursively write processed files to a new location, preserving subdirectory structure confirm error-free operation or list errors A nice-to-have is visual feedback of progress during processing. Up till now, the main purpose of this has been to downsize the ~3MB JPG images my digital camera makes for fast viewing—viewing images 640 pixels max side length instead of 3504 pixels, I can browse more efficiently, and watch my life in fast-forward, so to speak. So now I am moving everything to be done on Debian, and want to downsize my 80-GB collection to an intermediate resolution for my wife to work with. I'd like her to use a photo management app instead of doing everything by hand. I could of course use Irfanview for the job and then copy everything to a *nix partition, but that's sort of not the point. I know the heavily promoted Imagemagick can do batch conversion efficiently and is used as a backend for a lot of apps, but I'm not sure whether it can preserve subdirectory structure; this is a must because of over 200 subdirectories. The mogrify command changes the original image, and it seems inefficient to copy 80 GB only to downsize it. I'm sure that read-resize-write can be done preserving directory structure by using a script, and I'd be willing to do that in the future, but for now I lack experience and am not willing to use a script I don't understand. So to anyone suggesting this route I'd ask for help understanding the script. Otherwise, there seem to be few free apps that do batch resizing with the features above. I looked into Phatch, but it doesn't seem to let me set the exact resolution I want. I don't want to use Picasa until Google makes it free. Gwenview does batch resize, but doesn't seem to give all the options, unless I missed something. Any other choices on this task? Thanks (HowTos)