There's the matter of linking to copyrighted works: https://en.wikipedia.org/wiki/Copyright_aspects_of_hyperlink...
If your link is set up to make the image display immediately (that is, you wrap it in image tags, or as in one case, embed Instagram posts) then you may be violating copyright. What's more, in Europe, just a hyperlink to a copyrighted work violates copyright.
Conclusion: copyright is not about copying, it's about access.