Well known issue that has existed for a while, finding what is causing the bug has proven dificult. There are some cache changes coming at some point that may fix it.

You are not alone, same issue here. regardless of channel I use, DNS settings, or running as standard/admin i loose images on reboots.

They're probably quite aware of this bug, but it's so low priority and minor that it's on the backburner of the backburner.

Same issue here, the problem only started when there where alot of games installed .
Hopefully, one day they can fix this little problem.

Hahahaha. GOG fixing problems. You're a pretty funny person. Ever think of a career in comedy?

EDIT: Like that Linux version of Galaxy, even. Don't know WHY it's so hard, but I'd figure that would be something of a priority. But no, let's cripple Linux releases on GOG (some won't release a Linux version because "no Galaxy") and set back Linux gaming.

I don't even USE Linux any more, but come on people. This is ridiculous.

Mayby, i am still learning:) (watching alot of stand-up comedy on Netflix so i can get better)

funny
one of my steam icons just vanished :P

I found that just clicking on the games with missing icons usually fixes it.

What Lord_Kane said.

Just navigate to the game's page, wait a few seconds and the icon will show up. You don't even have to wait a few seconds on the page, it just takes a few seconds for the icon to show up.

Fix your shit GOG. This is why Galaxy is a slummy poor man's Steam.

Clicking on a game with a missing icon brings the icon back... for a while. Then it eventually disappears again. Sigh.

If only it was just missing icons--it changes the name of some games (and thus their sort order) when I click on them.

The Cultures series:
Cultures 1 --> Cultures
Cultures 2 (missing icon only)
Northland --> Cultures: Northland
8th Wonder of the World --> Cultures: 8th Wonder of the World

Others:
Legend of the North: Konung --> Konung: Legend of the North
Konung 2 (missing icon only)
Roller Coaster Tycoon 3 Platinum --> Roller Coaster Tycoon 3: Platinum!
UFO Afterlight --> UFO: Afterlight

Some lose their parentheticals:
Lords of the Realm (CD Version) --> Lords of the Realm CD Version
Master of Orion (Classic) --> Master of Orion Classic

The Heroes Chronicles games go from:
Heroes Chronicles - Warlords of the Wasteland --> Heroes Chronicles [Chapter 1] - Warlords of the Wasteland

Some game names simply replace "-" with ":". Others HAVE "-" in them, but don't change them (see Heroes Chronicles, above).

Two of the Spellforce 2 games have dashes in them that are replaced by colons (Shadow Wars and Dragon Storm, I think), but "Spellforce 2 - Anniversary edition" keeps its icon between reboots and so keeps its dash as well.

I original had 51 games that didn't have their icon after a reboot, out of about 377 installed.

It started when I just had 8-10 games installed...

For those not in the know, most of the games affected were sold in bundles, i.e. the Heroes Chronicles games, or how Heroes V includes multiple products. Others also come from unusual sales scenarios, while a handful just seem to have the problem for no reason whatsoever!

I have this problem too.