Hello everyone. So I am a complete newbie at this so I need a little help. I have four images, all different sizes. I am trying to combine them so they all line up next to each other in a kind of collage. I have done a rude form of this, but I end up with a white box in the corner since the images are not all equal in size. Three of the images I can resize to be about equal, but the fourth will look distorted. What I want to do is create a sort of upside down pyramid with them. The two largest images on top with the last two kind of centered below them. I just don't want that white section. I've tried deleting it, or erasing it but nothing works. Any help would be appreciated. Thanks.

Pyramid shape means you need a .png image with a transparent background.
You can delete the white background part only if you have alpha channel.
Menu: Layer/Transparency/Add alpha channel.
You can first position the layers (individual images), then merge them all to one, add alpha and clear white.
If you don't know how to merge, right-click one of the layers in layers box, and select ´merge visible layers´.



My advise is, don't distort images it's awful. If I could, I sentenced people to jail for doing it.
If you are using scale tool, keep shift pressed to resize proportionally.
Or crop part of the image if possible.

Or,
If you have the GMIC plugin, you could use the montage in there and set it to "horizontal or vertical" (Not horizontal or vertical array) and "aligned" (not scaled).
You still need to put your pictures as different layers after the first image, in alternating size.
Revert layer order (also a setting in montage), if they are not the direction you want. You can also cycle your layers until you get what you want.
If you give these a transparent background, you can add another layer of your favorite picture or colour to the back.

There used to be a script that would allow you to use one of your pictures for the background. I don't know if anyone still has it or if it even works in the latest gimp.