Any word from Microsoft on the HORRIBLE wallpaper compression issues in Windows 8?

So Windows 10 still haven't fixed this problem yet. I am so angry and disappointed. My beautiful wallpaper looks like **** AGAIN. Is it so hard to make wallpapers look good???? Editing theme every time when I change wallpaper isn't practical at all.

I've previously mentioned that this behavior exists due to the performance issues within this code path.  That reality hasn't changed and is probably not likely to change for this release.  In the interim, you can either use non-JPG source or hand-edit as it looks like you're doing.

The person who is currently working in this specific area (me) is, as you've likely noted from my comments in this thread, aware of this request.  I'm not excited about incurring performance problems in a critical pipeline for all users, so it's possible that this may require a special override if indeed there is time to account for this feature request in the future.

Again, howdy!  I'm the guy you'd want to bring this feature request to, and hopefully it's clear that I have listened.  There's not really anything more to say at this point: the system clearly imports at Quality=85%, and there are no overrides for that.  Until you see something from me on the subject, which would only happen after a beta or other significant product release of Windows, there is no way that the current behavior will have changed.  Again, note that this probably needs to not happen for all users so if this functionality is ever added it would likely require a specific override. 

I'm paying attention to you and your desires here, and look forward to improving this area as possible in the future.

Dear zachd,

I spotted this issue on Windows 8(.0) beta for the first time and reported it multiple times alread. I was completely baffled how this could have been broken since Windows 7. I also noticed that strangely enough PNG is fine now, whereas Windows 7 heavily reduced quality for PNG. I always thought that the code has been messed up by accident while fixing PNG or something and nobody noticed.

But thanks to your responses in this thread I get a grasp on the situation now. I really appreciate it that you took the time to explain the details a little further. Now I understand that this change was made for a reason.

Some time ago I created a little tool which replaces the 'set as wallpaper' option in the explorer's context menu and automatically converts PNG to JPG for Windows 7. So it looks like I just need to do the opposite for Windows 8 and up.

Btw, does the fact that PNG is untouched by the quality-reducing code path also apply for the slideshow functionality when using multiple PNG wallpapers?

I spotted this issue on Windows 8(.0) beta for the first time and reported it multiple times alread. I was completely baffled how this could have been broken since Windows 7.

It's important to note that this behavior is by design.  JPEG import at very high quality settings can be slower than is critically needed in a time-sensitive code path, and the quality difference is usually negligible.  I believe 75% quality is what the AMA recommends, and lives are involved in those images.  The former owner squeezed it up to an 85% import out of love and consideration, and that behavior has always and probably will always be intentional.  Don't panic upon that subject: it's just important to set a correct reality baseline for expectations here.  If people want to deviate past 85%, maybe we should let them in some fashion. :)

"I also noticed that strangely enough PNG is fine now, whereas Windows 7 heavily reduced quality for PNG. "

That predates my involvement.  Potentially PNGs were converted over first(?).  Now they're handled natively.  (I could check back in time if it really mattered, but I think that issue is likely academic at this happier point.  And the more time I spend working on now-stuff, the better.)

"Btw, does the fact that PNG is untouched by the quality-reducing code path also apply for the slideshow functionality when using multiple PNG wallpapers?"

Yes.  PNGs don't go through this code path.

Anyways, back to the grindstone for me.  <3

If you're using Windows 10, you can override the 85% quality value.  Create a REG_DWORD value named "JPEGImportQuality" under HKEY_CURRENT_USER\Control Panel\Desktop.  That value is capped at a low of 60, default of 85, and a max of 100.  Set it to the import setting you want - bearing in mind that high values will slightly slow you down on slideshow updates, for example - and then restart your system.  At that point, the next time you select a JPEG wallpaper source it'll be imported at that higher quality level.

Cheers,

-Zach

edit: This got referred to from elsewhere, so let's help avoid confusion.

Windows 7 imports all images at 85% quality.  PNGs is not natively supported.

Windows 8 imports JPEGs at 85% quality.  PNG is natively supported and is imported at full fidelity.

Windows 10 imports JPEGs at 85% quality unless you use this override.  PNG is natively supported and is imported at full quality.  The override registry value is literally handled as an integer and is capped at 0n100 / 0x64.  If you set it to anything higher, it'll simply be set to 100%.

I would also turn off Theme roaming in Settings :: User Accounts :: Sync your settings. Roamed themes have a maximum total size and so that can also cause further compression.

If you're using Windows 10, you can override the 85% quality value.  Create a REG_DWORD value named "JPEGImportQuality" under HKEY_CURRENT_USER\Control Panel\Desktop.  That value is capped at a low of 60, default of 85, and a max of 100.  Set it to the import setting you want - bearing in mind that high values will slightly slow you down on slideshow updates, for example - and then restart your system.  At that point, the next time you select a JPEG wallpaper source it'll be imported at that higher quality level.

Cheers,

-Zach