Unable to change Project Thumbnail - Unsupported Image Format

So I went looking for a quick bit of info for how to change the project thumbnail in the UE launcher, found a youtube video with the straight forward details, however when I go to Project Settings to change it I’m greeted with the message of Unsupported Image Format - this is before I’ve even tried to change it.

Still I tried to change it, the file browser only alows me to select PNG images, so nothing I select works, it still gives the error.
Thumbnail_2

In the youtube video the user is selecting PNG image files, so I presume they should work, plus given that’s all UE is allowing me to select I would have expected them too.

Does anyone know what’s causing this issue?

Sorry this is two years late, but I had to make my png 192 x 192 before it was accepted