What free program can I use to batch resize photos?

ImageMagick is pretty good if you want something from the command line, but if you'd rather have a graphical interface, XnConvert is free and really simple to use - you just throw all your images in there, set the size and format, and let it run. On Windows and Mac you've also got IrfanView which is basically free (it asks for a donation but works without paying) and does batch resizing without any hassle. It really depends on what you prefer, but any of them will get the job done.

XnConvert is really practical, but if you want something even more straightforward without needing to install anything, Photopea works in your browser and lets you resize multiple images at once. Now, if you have a lot of photos (like hundreds), then it's worth learning some basic commands because it's way faster than clicking through a graphical interface all the time - but for most people, visual tools like these two are more than enough.

If you have Python installed, a quick script with PIL or OpenCV will handle that in seconds - it's basically 5 lines of code and processes hundreds of photos at once. You don't need a GUI, just create a .py file, put your images in a folder and run it. For anyone who doesn't want to mess with code, what people mentioned works fine, but if you're into automation or have lots of images regularly, this approach saves time down the road.

Batch processing with FFmpeg is absurdly fast for that 🖼️ If you have it installed (or you can install it in 2 minutes), a single command like `for f in *.jpg; do ffmpeg -i "$f" -vf scale=800:-1 "small_$f"; done` resizes hundreds of photos at once without opening anything. For everyday use though, I'll be honest, I just use GIMP - open the whole folder, go to Filters > Batch Process and you're done, everything gets resized while you grab a coffee ☕

IrfanView is basically made for this: it opens any format, has batch rename and resize built in, and runs super light. The thing people usually miss is that the default output overwrites the originals if you don't change the destination folder before processing - and then you lose the quality of your photos.

People are recommending some pretty cool options, but you can't go wrong with GIMP if you've already got it on your machine - just go to File > Batch Process and resize as many photos as you want at once, without needing to install anything extra. Otherwise, I agree that XnConvert is super straightforward, but if you don't even want to install a program, Irfanview does it just as easily and super fast too, it's really lightweight and supports hundreds of different formats.