So it seems that the built in flash media manger for WordPress 2.5 is having some problem showing up images (or any kind of media) correctly in Opera.
I’m using Opera 9.26 on XP currently. No problems is encounter when uploading files as I can see that the filename is added into the Gallerry. The problem is actually when you try to insert the image into your post by pressing the “Show” link. Guess what, nothing happens.
But if you know a bit of HTML and just look into the source, you can still get to your image file easily. That’s how I manage to insert the image above anyway.
It looks like the issue has been reported and pushed into 2.6. Let’s hope that the fix or a branch will be released soon as this is really bugging lots of opera users.