How to make a transparent picture a non transparent *GIMP*

Question

A friend of mine sent me an image that is almost completely transparent as a sort of encrypted code type of thing, the only way I can see it is if I go into the default paint program and use the bucket tool, and even then I just see a colorless, slightly inaccurate outline of the image.

So I looked around for alternatives, but after googling "How to make a transparent image non transparent" and a bunch of versions of that question I just got one answer from this site on how to do it with Adobe Photoshop (which I don't want to have to pay for just for this) or from some other site with some complex program. I heard that GIMP is a decent free bit of photo editing software and downloaded it before messing around for a bit to see if I could find a way to turn the image from almost completely transparent to its original format.

I failed, only managing to load the nearly transparent image and fool around with it before ultimately giving up, the closest I got was when I adjusted the brightness and contrast (if I remember correctly) and got a similar, inaccurate, outline of the image but in a orange/red version with a black background rather than just black and white that I get from using paints bucket tool.

Help would be appreciated, however if its not possible to revert the image back to its original format then I'm alright, I just want to know if its possible or not and if it is then how I can do it with GIMP (or, if necessary; some other free, clean, and easy to download/use software)

Answer 1

I would say the best way to make it not transparent would the (in GIMP) open the file, make a new layer underneath the image of a color of your choice, then save it as a .JPG since they natively do not have transparency.

Hope that works out! It should without issues.

Answer 2

In Gimp we can replace an alpha transparency channel by the background color from the menu Layer > Transparency > Remove Alpha Channel:

Answer 3

As an addition to previous answers, if you still have this thin outline, for me the easiest way to get rid of it is this:
1. select transparent part with autoselect tool (or any other way that suits you)
2. edit selection by either increasing it by 1 px or by feathering selection to 2-3 px.
3. delete everything selected.

Answer 4

Just want to let you know that now you can find solutions to achieve this using an online editor like pixteller.com or canva...do not get it "why using software tools anymore?"