ImBatch is an interesting batch processing tool which can convert, resize, rotate and carry out other operations on lots of images in a single operation.
Adding images is as easy as dragging and dropping them onto the program, and ImBatch supports plenty of file formats: BMP, DIB, RLE, TIF, TIFF, FAX, G3N, G3F, XIF, GIF, JPG, JPEG, JPE, JIF, PCX, PNG, TGA, TARGA, VDA, ICB, VST, PIX, PXM, PPM, PGM, PBM, WBMP, JP2, J2K, JPC, J2C, DCX, DAT, PSD, WDP and HDP.
Clicking "Add Task" then allows you to choose exactly what you'd like to do with these files. The options available are "Save As" (convert format), "Resize", "Rotate", "Soft Shadow", "Flip", "Round Corners", "Convert Colours", "Convert to Gray", "Set Tag", "Remove Tags" and "Shift Time" (the final 3 all relate to EXIF tags).
As you combine these tasks, so a Live Preview window shows you what they'll do to your target image.
There's even a task command to upload your processed images to Facebook, so you won't have the hassle of doing this manually.
Version 5.5.0 (see full changelog):
Added Set DPI task.
'White Balance' task: added the ability to select a color for white color.
'White Balance' task: added the ability to select white color in Preview.
'Resize Canvas' task: added the ability to set the cropping frame on the 'Before' tab of the Preview window.
'Save To Animated GIF' task: added the ability to optimize the file.
'Save To PDF' task: added the ability to save the pages in order (only for multithreaded processing).
'Save As' task: fixed saving to DDS with multithreaded processing.
Added the ability to turn off replacement of spaces with underscores in file names.
Preview window: Now when you update, it does not automatically switch to the "After" tab.
'Optimize for Web' task: updated interface.
'Resize canvas' task: fixed setting of height in the "Borders" mode, if you select "%" for units.
'Watermark' task: Corrected the watermark movement in the Preview window, if selected non-pixels for the units.
Task processing: now disabled tasks do not perform the initial processing.
Image list: Corrected sorting by name for names with numbers.
Image list: fixed image movement.
ImBatch provides plenty of image batch processing power, yet remains fairly easy to use.