커버사진 좋아여쯤 is not correct as written.
It could be:
1. 커버 사진(이) 좋아(서) 여쭘 = I'm asking you because I like your cover picture.
2. 커버 사진(이) 좋아졌음 = Your cover picture has gotten better.
It is probably #1 as it has a difference of a single stroke (ㅡ vs ㅜ).
여쭘 is the -ㅁ ending (a curt ending used online) of 어쭈다 (honorific form of 어쭈다 = ask; inquire).
You would normally say it like "(님의) 커버 사진이 좋아서 여쭤 보는 거예요", but many people like to talk like a robot when they're online :-)