Transparent Backgrounds

You know what it's like, you got this great image you want to use but it has this naf background and, well we all know you can do better. In Gimp if you don't know how, it's not that easy to work it out. I worked it out quite by accident and promptly forgot what it was that I did to achieve it, typically. So I am writing this to remind me how it is done, and if anyone else wants to know how, well here it is.

Open the image you wish to edit in Gimp, if the image being open has a plain background you task will be much simpler we will assume you do. Adjust the size and orientation of the image to your liking and save the image to disk using the .xcf format type. The .xcf format is native to Gimp therefore all the objects you have taken time to construct are again editable in this format. You can if you wish save the image in any format you want but if at any time you wish to alter the image, perhaps spelling, wrong date or imperfection to the image for example, this becomes harder to do in any other format type.

We are going to use as an example this image below.

Isn't he cute, this image is a jpeg of 300 x 310 pixels if thats what you want to work with that's fine, you can leave the image as is. But their is a problem, the image itself is great the background is naf, and well we want to dispose of it, so we can replace the background with anything we want. With this image now installed in Gimp and having all the alterations made to size and orientation and so on we save this image to disk in native format, this we do using the 'save as' feature in file menu. You can retain the filename intact just swap the extension shown .jpg with .xcf, hit the save button.

Looks not half bad even now, true he does until you want to place him on a different coloured background other than white then he sticks out like a sore thumb. You could just colour the background to the colour you want. But that is not what this tutorial is about so we will dispense with what could be done and do what we originally intended.

Because the background of this page is white I will change a small portion of it so it will be possible to see the changes made to the image. I have chosen an off white or cream colour to display the changes in the image, this will show through the transparent parts of the image.

The image itself in Gimp needs to be edited, choose a tool that leaves no alterations to the image, I use the "Move Layers and Selection Tool" it looks like a cross with four arrows on it, pointing north east south and west, select this tool and move you cursor to the picture itself right click your mouse to bring up the context menu, select layer => Transparency => Add Alpha Channel.

Next select the "Wand Tool" and place this anywhere on the image you wish disposed of, in this case the top half of the white. The last thing we need to do having selected the area to be changed is to right mouse button click for context menu, and select "clear" from the edit menu.

That is pretty much it, select the bottom half of the image with the wand left mouse button click, then right mouse button edit => clear. This second image has been exported as a .png (portable Network Graphic). Not all browsers can handle this image format but most do, at the time of writting this tutorial I am only aware of two file formats that handle transparent backgrounds these are .gif (grapical interchange format) & .png, there may be more, however I am not aware of them.

	The top is transparent to show the cream behind the edited image

You now have an image that you can use on any backgroud. Have fun with Gimp.