Open Source graphic tool and alternative to Insane Bump
AwesomeBump is a free and open source graphic app written using Qt library. It was made as an alternative to known gimp plugin Insane Bump or the commercial tool Crazy Bump. It is designed to generate normal, height, specular or ambient occlusion, metallic, roughness and other textures from a single image. Most of the image processing is done on GPU so the program runs very fast and all the parameters can be changed in real time.
JPEGView is a lean, fast and highly configurable viewer/editor for JPEG, BMP, PNG, WEBP, TGA, GIF and TIFF images with a minimal GUI. Basic on-the-fly image processing is provided - allowing adjusting typical parameters as sharpness, color balance, rotation, perspective, contrast and local under-/overexposure.