Not that they aren't funny, but half of these are worst album titles and not worst album covers.
What most of these are are examples of "bad art", which is related to the concept of "ugly beauty". "Bad art" is impactful but the impact seems to strongly differ from the perceived intent of the creator. How important creator intent is to an art objective is highly debated. There is also the issue of how humorous the object is perceived to be in a particular culture, again generally as opposed to the creator's intent. Some of the objects, though, are intentional parodies (pranks, academic illustrations, etc.).
One form of humor is "taking oneself too seriously" aka "going off the deep end to seem arty", as with Zepplin's
Houses of the Holy, a cover that I would put into the top 10 of most eyeroll-worthy. Another for the "trying to be arty and looking silly" top 10 is Fleetwood Mac's
Rumours. The pseudo testicles are the most cringe-worthy element in a complex display of cringe. If the cover were to have only Stevie Nicks in her pose and the band name/album name then it would be fine. If it were to only have Mick Fleetwood in his pose, sans dangling bits, it would be annoying but at least more dryly comical. But, the actual cover is overloaded, even without the
truck balls.
Another failed artiness attempt:
It's slightly cute but a bridge too far.
Another attempt at artiness:
"Embarrassing" and "worst" are often not synonymous. Wilde quipped that the worst thing is not being talked about rather than being (negatively) talked about. This points to the worst outcome for a human, which is to be socially invisible/dead.
Xiu Xiu made an "experimental" (a convenient catch-all for work shoddiness) release called
A Promise which has an intentionally awkward/embarrassing cover. It fits well with most of the examples provided here so far, especially the CD release with the model positioned sitting up. The music of the release was so amateurish that I was inspired, when I ran across it on Youtube many years ago, to make lo-fi low-production stuff myself (stop worrying about production quality). I felt I could do a lot better (not that it would be difficult to exceed the "Xiu Xiu" standard, the sonic equivalent of Sloth Jesus), including the quality of the cover art. But, I had neighbors right on my wall and didn't want to embarrass myself. Speaking to today's pop music, I also, just recently, strongly considered releasing a parody medley of
Turn Off the Lights and
Where Will I Find You? — two songs I was accosted by for lengthy durations (one while shopping and one while playing tennis).
I won't post
A Promise here because it has the dreaded "full frontal" male nudity which ruffles more feathers than the breasts already posted. There are box-censored versions which are even more awkward, though. I wasn't going to post Xiu Xiu covers, also, because considering that "band" mainstream enough to bother with is pretty debatable. If I had been drunk in the shower with a Radio Shack tape recorder running the result would have been better than
A Promise. The useless "review site" AllMusic, though, seems to think they're a band.
Going back to my original point, the true worst covers are the ones that are so boring they don't make any impact at all. Some of the more recent Xiu Xiu covers are like that. Many New Order covers are like that (
Low-Life,
Brotherhood,
Get Ready). Even when they make an impact, however slight, some of them don't have the impact that fits with the character of the music. Perhaps that's a reaction against the strong emotional impact of the band's earlier incarnation, with a cover like
Closer's. Curve is another band that comes to mind for banal covers.
One thing that seems to be a tendency is for pop music artists to release increasingly dull covers over time, as their music loses interest. It's the opposite of most classical composers. Most of them improve over time. Here are a few examples of banal covers:
Pat Benatar, Go. (Tries too hard to be youthful in multiple ways and ends up seeming plastic/corporate/vacuous.)
Large portion of the cover is pure banality.
Stupid name and cover covered with banal text... Band name and album name too prominent again.
Led Zepplin, Physical Graffiti. (Not as bad as a Curve cover or some of the New Orders but dippy and dull.)
It's hard to out-do New Order for lousy covers (considering very famous bands/artists and trying to ignore indie), even though two of theirs are nice enough (Power, Corruption, & Lies and Technique). I actually had the thought of putting just the word No on a cover once, long before this was released. It's really not that clever. As a visual piece it's very boring here.
New Order's
Get Ready
New Order's
Low-Life. (Really... no one wants to see that ugly mug.)
Dull.
Curve evidently got the memo about trying too hard and went too far in the opposite direction.
There is the art of understatement and also the impression of not making an effort. Best way to really make that point is to not release anything, eh Xiu Xiu?
Sometimes camp covers can be pitch-perfect, as with Tammy Faye's
Run Toward the Roar. I bought the LP at the thrift store just for the cover. It has a snazzy inner shot, too.