Accept it: there was at least one point in time when you had to resize a large number of photos in Linux in one go, and you wished you had known a tool that would do that. Well, certainly, you hadn’t heard of XnConvert. This nifty little ultra-configurable cross-platform utility does that, and infinitely more to as large a batch of photos as you can pile up on your computer.
XnConvert supports more than 80 different operations, like metadata editing; rotate, crop, resize transforms; brightness, contrast, saturation adjustments; blur, emboss, sharpen filters; masking, watermark, vignetting effects. While batch converting images, you can either add individual files or a complete folder of images. Furthermore, you can do a combo of operations on, say, all 23 images, of (1) resizing to 800×600 (2) applying the oil painting filter (3) adding a signature text (4) putting a 3D border — all in one go. Each operation/action comes with its own set of settings.
You can save the output of batch operations to files in a folder, or upload directly to your Picasa or Flickr account. The exported output can be saved in several popular and not-so-popular file formats (most with customizable settings). XnConvert remembers your selected list of actions the next time you start it.
Check out its more powerful cousin XnViewMP as well to get a multimedia viewer, organizer and converter all in one. And if you are a Windows user, you may want to check out its lightweight cousin XnView, whose version 2.0 was recently released. XnView is also available on mobile as XnViewPhotoFX.
Editor’s note: This is not an open source application, there are many open source applications like Phatch which also offer great conversion.