This guide will guide you through installing GIMP on mac OS X 10.4.x with easy-to-follow and clear instructions.
Insert your OS X install disk and locate the Optional Installs package. Double-click it.
An installer window will appear. Continue using the buttons at the bottom until you reach the installation type step. When you have reached this step, expand the Applications subsection in the tree by clicking on the triangle next to it, and check element X11. Once this is done, click on the Update button to continue, and perform installation.
If ever you lost the install disk, take a look at this.
Next, you need to update X11 to at least version 1.1.1 if you got an older version. Select Software update from the Apple menu and update X11.
Then, download GIMP from the Wilber Loves Apples file downloads. Scroll down to the MacOS 10.4 Tiger subsection and pick either the PPC or Intel build depending on your computer. (If you do not know which one to download, select About this mac from the Apple menu)
Once downloading is done, double-click the dmg file. Drag and drop the GIMP icon to your Applications folder.
You can now eject the disk image by dragging it to the trash. You can also delete the dmg if you wish.
There's one small operation we can now perform to make it easier to use (note that this is not necessary). Doing this will save you many unnecessary double-clicks during editing by not requiring you to activate GIMP windows before you can click on them. While Gimp and X11 are closed, open /Applications/Utilities/Terminal, and paste the following commands in it and press enter:
defaults write com.apple.x11 wm_ffm -bool false defaults write com.apple.x11 wm_click_through -bool true
A few more things to note:
Menus in Gimp will not appear at the top of the screen like regular OS X menus, but in every window instead (this happens because Gimp comes from Linux where menus are like that. A non-X11 version of Gimp, when it comes, should have the menus at the right location.)
When you open GIMP, there will be 2 icons in the dock: Gimp itself and X11. You can mostly ignore X11, but just be aware that Gimp requires it to remain open while it runs to work.
Do not quit Gimp from the dock, instead quit from the File menu or by using the keyboard shortcut. This is one more limitation caused by X11.
Keyboard shortcuts by default use the Control key instead of mac standard Command. You can make it use Command by following the instructions here.
GIMP can now be opened by double-clicking on its icon in your applications folder! Note that the first time you open it, there will be a slight delay before anything appears on screen.
Happy Gimping :)