Photopus

Photopus is a clear-cut software application that enables you to tweak images and change their extensions. It offers support for a wide range of file types, including BMP, GIF, PSD, PDF, PNG, TGA, TIF, ICO, EMF and HDR.

After a fast and uncomplicated installer, you are greeted by a clean window with an intuitive structure, representing the program's interface. Photos can be added from individual files or entire directories.

You can preview pictures in the main window, check out file information when it comes to the name, format, size, dimensions and date of last modification, adjust colors (brightness, contrast, balance, gamma, hue, saturation), crop, rotate and flip photos, as well as apply plenty of effects, like black and white, borders, despeckle, diffuse, dilate, edge enhancement, grayscale, or negative. All these changes can be previewed in real time.

Photopus also lets you rename files by changing them to uppercase or lowercase, specify a new size in pixels or percentage, maintain the aspect ratio, set the DPI, choose the output directory, as well as convert the images to other formats and establish the quality and color depth. The project can be saved to file and later resumed.

We haven't come across any stability issues in our tests, thanks to the fact that the tool didn't hang, crash or prompt error messages. It had a good response time to user commands and carried out tasks rapidly while remaining light on system resources usage.

To sum it up, Photopus comes loaded with a wide range of image filters and support for numerous file extensions to help you adjust and enhance your favorite photographs, and it doesn't require previous experience to work with. Plus, it's free.