ArtWeaver is a light weight desktop image editor. Functionality and tools resembles Photoshop interface but it is not as powerful as Photoshop. If you are looking for a simple image editor to quickly edit images this is one of the Photoshop alternatives you can consider.
If you have ever used Photoshop then ArtWeaver is easy to use. It offers more than basic photo editing tools. It also supports layers like Photoshop. There are a handful of brushes available to use. Supports gradients, filters, image adjustments like hue/saturation etc.
This is not all ArtWeaver also supports plugin architecture, so it can be extended by using plugins. There is a portable version also if you prefer to have this image editor in your USB stick.