ImageBatch is a very useful thumbnail creator and photo converter. ImageBatch is a free lightweight batch converter for images, based on LibGD and EasyBMP graphic libraries. Currently supported image formats are JPEG, PNG, GIF and BMP.
With ImageBatch you can convert your images from one format to another, resize, crop, rotate, flip them and draw watermarks as well.
The interface was designed to "Keep it Simple", but without sacrificing any of the features you need.
The license of this software is Freeware, you can free download and free use this image processing software.