This week, I will cover a piece of software that is fully compatible with Photoshop: GIMP.
GIMP stands for GNU Image Manipulation Program. It allows a user to do EVERYTHING that Photoshop does and more. A person can create business cards, movie posters (full size), simple animations, brochures, and even comic books using actual photos. Approximately 95% of the Photoshop brushes and filters work with incredible ease in GIMP.
There are several online resources and PDF books that are free to use, and you will find many links to these at my blog. You can also find books (for a modest price) at Barnes & Noble and other book stores, both brick & mortar and online. They can cover very specific issues, such as photography or everything GIMP can do in great detail.
You will see in the photo what GIMP looks like when it's started and a user selects File->New and clicks "OK." There are three panels. On the far left is the 'Tool Chest,' which includes all the paint brushes, pencil tools, fonts, morphing tools, and sizing tools. With these, you can create squares (or rectangles), circles (or ellipses), and triangle: enough to create all of nature. In the middle is the fractal generator for repeated symmetrical patterns such as natural landscapes.
To the far right are layers, gradients, and patterns and a tab for adjusting the red, blue, and green of an image. Using layers, you can create spectacular effects, such as a star background with a planet of your design with a personal logo. Using gradients, you can have a background that is unique to you.
One of the best parts of GIMP, in my opinion, is the filters menu. This menu has preset filters for doing many cool things, such as “cartoonify,” which takes a photo and turns it into a cartoon in a couple of clicks. You can also take a photo and make it into a mosaic, age it through sepia, or make it look like a newsprint photo. There are filters to colorize black & white or do the opposite. It is even possible to create your own custom filters through a built in language called Script-Fu for which there is a ton of documentation and very simple scripting language (more so than HTML).
GIMP is available for all computers and OS's (including RPi). Speed depends on the hardware used to run GIMP.