Preview of attachments in mkv files

[LeMoi]

Hello there,
I just discovered the Icaros tweak, but I couldn't manage to do what I want to: using attachments jpg as thumbnail for mkv files.
I checked the option in settings, but it doesn't work, every mkv file I own has 1 or 2 cover files, and the tweak doesn't allow to display any of them, it justs shows a preview from the video.
Is there something mandatory in the filename or any property of the attachment that would allow it to be used as thumbnail?
Thanks in advance for your help

[LeMoi]

I was told that the attached jpg has to be named cover.jpg...
Is it possible to add an option to use first jpeg file in attachments, instead of looking for the cover.jpg file? Thanks in advance!

[LeMoi]

Is there anybody here in the development forum?
Is this the official forum, or is there another way to reach the author(s) of this tweak?

[catweazle]

Is there anybody here in the development forum?
Is this the official forum, or is there another way to reach the author(s) of this tweak?

you're completely right here, but xanashi seems to run out of time ...

I do that like you want to. I'm putting just the desired picture inside the movie, not looking for names. And if I see another nice cover, I put it inside too, just for being safe. It'll be shown the first one and the app being used for putting in is MP3Tag.

[Xanashi]

I'll be implementing an option to use any image file as cover in MKV soon. 
Thanks for your input.

[LeMoi]

Big thanks