Bug 491184

SUMMARY
When launching Gwenview for the first time in a session, it takes a very long time to load images, particularly if the drive is not the boot drive. This happens regardless of which drive or folder I open, but after the first launch of Gwenview things are significantly faster. There is still a 5-ish second loading process.

The loading process causes Gwenview to be very unresponsive, so there is a lot of delay when zooming into images initiating actions such as a crop, etc. I was in the process of making another report and was using Gwenview to open some screenshots for comparison, and it took several minutes before everything fully loaded and I could get into using Gwenview. Once the number at the bottom of the screen actually represented the number of images in that folder and so had fully loaded it, things were smooth. 

This happens across SATA SSDs and m.2 NVMe SSDs, and also happened when I had an internal HDD which is no longer connected.

After this period, while it still takes Gwenview some 5-ish seconds, it's much faster than several minutes on the first boot. I have been able to reproduce similar behaviour on a separate device, although it is much faster (less than a minute) it still takes time for Gwenview to "warm up" on a first boot.

Perhaps Gwenview is trying to parse all images across drives or something? Since this happens regardless of which folder I open. There are a significant amount of images and videos across my devices, almost 70,000 on one drive on my PC. These are primarily large, uncompressed Steam Screenshots (thousands of these are 15-17mb). Maybe the volume and size of the files is causing Gwenview to take a long time to "load"?

Ideally, Gwenview would be as close to instantaneous when opening an image as possible, assuming adequate hardware and drive speed. 

STEPS TO REPRODUCE
1. Perhaps a prerequisite is to have a significant amount of high resolution, large image files. 
2. Open Gwenview for the first time on a boot.
3. It is significantly slower than you'd expect, taking at minimum about 30-45 seconds but upwards of several minutes before it can become usable.
4. Close Gwenview and re-open the image
5. It loads up much faster (the number at the bottom-middle of the display parses all images in the folder much more quickly.

OBSERVED RESULT
Gwenview is quite slow on a first load, but is faster on subsequent loads (although it could still be faster). Until it has fully loaded, it is too slow to interact with. As an example if you take a screenshot and want to crop it, it can take a very long time if you haven't opened Gwenview in that session. Even if you have, it is still slower than what it ideally should be.

EXPECTED RESULT
Gwenview should not necessarily load images faster, but become responsive faster, to increase workflow speed.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.1.3
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2
Kernel Version: 6.10.2-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 3700X 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 7900 XTX

ADDITIONAL INFORMATION
* This isn't new behaviour, it has been this way for many years, I just never got around to reporting it before :-) 
* I had a look around in the settings and didn't fine anything. Looking online it seems like people have complained about this before, but every issue I saw explicitly mentioned high CPU usage while loading. My CPU usage does not increase significantly overtime when waiting on Gwenview (there is a spike up to around 50% when opening but it dies down quickly).