drop in picture quality when I attach images

[jhonpog]

Hey all I am trying to build a bit of thread of my miniatures collection with a phone camera. I am getting reasonably in focus pictures but for some reason when I attach them to a post they upload slightly blurry or out of focus.

anyone experienced this?  Are the images being compressed maybe?

My painting and photography isnt exactly great I need all the help  can get thanks!