Gimp won't allow me to copy and paste a transparent image

Solution 1:

This "works for me" - actually the only I see of it not working is if one does edit->paste on GIMP - it them creates a "floating selection" - which is a temporary layer which exists mostly to allow positioning of the pasted contents - and them "anchor" the floating layer on a opaque, background layer. The transparency was there, as expected, but "anchoring" is the act of fixing the pasted pixels on the background. Note that just clicking on the image, outside the selection will anchor the pasted data in this way.

The options you have are either, after edit->paste click on the New Layer button (frst button on the layers dialog - or through the Layer->New Layer (Shift + Ctrl + N) menu action: this will promote the pasted contents to a full layer which retains its transparency. Or, you might as well just paste with Edit->Paste As->New Layer to start with: no floating selection is created.

Solution 2:

The data saved to the clipboard when copying the photo may not support the aplha channel/transparent data. What works for me is opening the transparent picture in GIMP, then clicking and dragging the layer from the transparent image into the project I'm working on. Hope that helps!