How does it work? It's very simple. Just add a folder of images, or select all of the photographs that you need to convert. Once they're all grouped together within the Convert Hub window, you can specify the parameters you want your results to have: extension, size, rotation, orientation, etc.
After that, just choose the destination of the results and click 'convert'. Convert Hub will take care of the rest.
This program possesses more than 40 popular image formats, allows you to specify JPEG quality, and can change the size of any image by percentage or pixels.