Many of my .png and .jpg files are generating some low quality thumbnails. It seems to be mostly drawings or sketches, as I draw in my free time. The thumbnails generate correctly when viewed in Windows Explorer. I have dopus up to date, and am running Windows 7 x64.
I have tried playing with cache settings, using lossless compression, and even tried clearing the windows icon cache and dopus cache.
Is there some kind of hidden setting where I can change how dopus generates thumbnails for pictures?
Picture of the issue has been included. You can really see how blurry many thumbnails appear. I pulled up dopus and explorer side by side -- with dopus being on the left in this screenshot. I have just erased a bunch of stuff for privacy, the thumbnails in dopus really do look that blurry.
I think this issue affects Explorer as well, in fact.
The underlying problem is that both Opus and Explorer will cache a 256x256 version of the image and then scale that down to your selected thumbnail size, so the image is being scaled twice. That's fine for most image types but can result in a big loss of sharpness with line drawing like these.
The difference with Explorer is in what it does the first time you thumbnail an image: It will cache a 256x256 version of the image, but also directly scales the full-size image down to the current thumbnail size, only for that first request. So it looks good, but only for that first request. If you push F5 to make Explorer re-generate the thumbnails using its cached version this time, you get an image very similar to the Opus one.
I think the only way to avoid the extra scaling is to set Opus to display 256x256 thumbnails, so that the cached image can be used directly without any additional scaling. (Disabling caching won't help, since the thumbs for the current folder are always cached in memory for quick resizing, and the caching option just stops them being written to disk.)
The blur is especially present when you downsize the thumbnail.
Maybe its because the image is grayscale. When I convert your image tor RGB the thumnails gets a tad sharper.
Just my observation
AH - I see now. Settings my thumbnails to 256 x 256 instantly made my image thumbnails clean up and look perfect. Sadly, my laptop has a terrible resolution of 1366 x 768, so with 256 thumbnails I only get 4 pictures wide on my screen vs the 6 i was getting at a custom setting of 170 x 170, but I will gladly live with the fixed thumbs!
