Bug 420252

SUMMARY
In album views, the thumbnails of all my mpo (3d images) file appear as corrupt data, while the thumbails of the jpeg files are correct.

STEPS TO REPRODUCE
1. create a folder f1 containing one or more mpo files
2. disable the current digikam database by simply renaming it, to force digikam to create a new database on next run.
3. start digikam. This should allow you to create a new database. When asked, select the filder f1 as the photos folder
4. digikam will then generate the thumbnails for the photos

OBSERVED RESULT
The thumbnails of the mpo files appear as corrupt data (mostly grey with random patterns)

EXPECTED RESULT
Well, the thumbnails are expected to look like small versions of the photos

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Linux Ubuntu 64bits 18.04
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
- thumbnails for mpo files used to be correctly generated (only thumbnails for newly imported MPO files are corrupt), so I beleive there has been a regression at some point, but I can't tell with which version of digikam the corruption started. All I know is that digikam 6.3.0, has the same problem.
- I initially thought that my MPO files themselves might be corrupted, but it doesn't seem to be the case, as I tried to reimport import an MPO image which had a proper thumbnail, and its newly generated thumbnail is corrupt as well
- I can send you one of my MPO files if needed.