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 5.1.0 (see full changelog):
Added "Save In CMYK As" task.
Added "Save To Animated GIF" task.
"Save As" task: added extended configuration options for TIFF and DICOM formats.
"Set Tag" task: added support of image and file attributes for the text tags.
"Watermark Text" task: added the ability to wrap text.
Added the ability to set templates for date/time tags.
Selecting color from the screen: fixed work with multiple monitors.
Selecting color from the screen: added the ability to cancel the color picking.
Fixed a rare error that happening while simultaneously updating the preview and loading image for hint.
"AutoCrop" task: fixed processing the preview.
"Save As" task: spaces in the name are replaced by underscores.
"Save As" task: fixed error when saving in multi-threaded processing.
Image Monitor: fixed error on loading of the non existent folders on start.
ImBatch provides plenty of image batch processing power, yet remains fairly easy to use.