In case you are not aware, GIMP is an open source image editing software that is bundled in most Linux distro and is touted as the closest alternative to Photoshop. It comes with plenty of toolset and filters for you to create/edit your image, and the best thing of all, it is free.

This how to help you to add your own grub splash image(image in the boot menu).

1. Open any picture in GIMP
2. Resize canvas size to 640x480 ( If you are an expert you can add higher resolutions)
3. Now Save as .png or .tga format (in some versions jpg also works)

In Ubuntu, the Archive Manager (or file-roller) has make it easy for anyone to compress and zip up a file or folder, but if you have a large file, say 20Gb, and you want to back it up to the CD/DVD, you will find that no amount of compression can you reduce the file size to fit into 1 CD/DVD.

KDE's window-specific settings feature gives you a fine level of control over the way windows behave. It lets you change settings such as minimum/maximum size, position, overlay, and transparency. The GIMP uses multiple windows to select tools, tool options, and other items used in the process of image editing.

GIMP or GNU Image Manipulation Program is a freely distributed piece of software suitable for such tasks as photo retouching, image composition and image authoring. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, a image format converter, etc.

Seam Carving is perhaps the the most interesting image resizing technology out there. It works by changing the height and width ratio of the image without distorting the image itself by croping the image. Now Seam Carving it possible with the Gimp.

The Eye of GNOME supports a variety of image file formats. The GdkPixbuf library determines which file formats Eye of GNOME can load and save.

GREYC's Magic Image Converter (G'MIC) is a image retouching tool which has been made available as a GIMP plugin. G'MIC comes with a large number of pre-defined image filters and effects (more than 190!).

You don’t need to have played with a digital SLR camera for long to run into the continuing frustration that is RAW images. RAW images offer very high image quality without the nasty compression artifacts of often found in consumer cameras using the JPEG format.