Problem Details:

You can get unsubmitted maps get any preview you want, and I found out how
Look at the number of a map (you want a thumbnail of) for example, 110547
Then get a .mp3 of the songs you want to map, and give it those numbers to the name. For example 110547 song.mp3
Open it in editor and do a few things (set metadata/timing and put a circle) (Not sure if needed, but I only noticed it after this)
Then you'll see the map has the incorrect thumbnail
I had this happen quite a lot, and maybe if this gets fixed, all wrong issues about it get fixed, as it strangely enough is tied to the beatmap number of the folder

Video or screenshot showing the problem:



osu! version: 20150401.2

Not sure if ninj'd or duplicate but t/320136

I named mine "168388 Soul Eater - OP 1 Resonance Full HD.mp3", dragged it to the songs folder, set timing, and created a couple notes. The map's background doesn't show (should there be a bg file in folder for the bug to work?)

Basically what you're saying is...
If you have a folder with numbers, osu! takes that number as the beatmap's ID and sets the thumbnail to that beatmap's thumbnail?

Edit1: This probably similar to BSS saying your beatmap isn't your if the folder starts with numbers.

Edit2: Confirming (low priority for now).

It seems The BeatmapSetID also gets changed to a value instead of -1 if this happens
Should I make a new post for that? Or not, because this is the case of that problem?

baraatje123 wrote: 5t724b

It seems The BeatmapSetID also gets changed to a value instead of -1 if this happens
Should I make a new post for that? Or not, because this is the case of that problem?

Nope. It's because osu! uses the .mp3 name as the beatmap folder name, and the numbers at the start of a beatmap folder name get used for the ID, we know this. Anyhow, I'm pretty sure TheVileOne is/was/is going to work on a solution for this. Or at the very least he's aware of this issue. Anyhow, the reason this issue happens is still the same, so there's no need to make a new thread.