Linked image blurred after export to PDF

Hi!

I'm new here. I was doing a design for a wall sticker. I inserted a linked images and there's also some vectors elements in it as well.

My problem here is, after I exported it to PDF/Jpeg, only the linked images came out blurry. The other vector elements are just fine. FYI, the image I use is a high resolution image. Really appreciate it if anyone can help me with this. Thank you in advance.