What is a transparent png? (Opensim/SL use jpeg2000 internally). – Do you mean a texture that is uploaded with an alpha channel?
If you want to set a face transparent, select the face and use the Trans button. In this way you ensure it is transparent across all viewers and grids (they all know about this uuid).
Also Alpha mode shall be set to Alpha Blending for such textures.
View attachment 173
ok... I tested the same and it worked here. When you open the texture, the dimensions and (alpha) is displayed in the lower right of the floater if the texture has alpha.
Windows or macOS version of the viewer?
There is every reason to move to 0.9.2.0 - there is an ocean of fixes and updates, also to prim behavior.
... I can't say I have done much testing on flexis. I generally regard them as big lag inducers, but of course they have their use.
Since I cannot reproduce, you'd have to pass me one of the textres that does not work for you for verification.
Then there is something completely wrong with your installation, because it does not behave like this in any other installation.
Is this with your standalone?
To me it sounds like a permission issue, where you don't have the permission to write updates back to the region and region database.