Veqa Image Marker - Veqa Image Marker is a PHP tool to mark Web images on the fly. Features 40 mark presets, X/Y offset positioning, opacity, watermark security, and more. Supports JPG, GIF (and animations), PNG, BMP; and GD, ImageMagick, MagickWand.
iMarker - It can mark text in images by highlighting the important parts using the mouse pointer, similar to manually color marking. Images from websites and screenshots can be quickly pasted and edited.