I came across 2 amazing tools for image manipulation and batch processing. In one of my projects I had to deal with thousands of images and batch converting name . I will give examples of usage as well.
1) In the first case I had convert a large number of images and I also had to put the file name onto the image , its painful to open each images, get the file name and save it back along with the name using photoshop. Hence I used Irfan View
2) And the next problem was I had to convert a bunch of EXR files into tiff files, irfan view is capable of batch processing, but I had multiple folders with thousands of files inside it, I was trying to compile image magick for windows with openEXR support and then I came across http://www.xnview.com/en/ , a brilliant piece of software thats freeware and also has command line tools available
Download them and have fun while they batch process all your images !!