I have a folder with the following files inside: a.jpg b.png I open b.png file, I select "Save as" and I change filetype by selecting JPEG from the available list under Filter options. This triggers GWenview to change the Name form from b.png to a.jpg, instead of having a b.jpg filename. It seems that he sees the first available file in the folder with the same extension you just selected, and it selects its name. So I have erroneously overwritten a.jpg file, losing its data. Reproducible: Always
Interesting bug. I'm not able to reproduce in Gwenview 17.11.70 in KDE Neon. Looks fixed.