I like the bang !i for image search. For one, it appears to go to Google which is only partially good.
I went to https://next.duckduckgo.com/?q=images+of...
and got some nice results but …
Let me user decide what resulting sizes such as S,M,L,XL,XXL,Giga options could be incorporated or a user defined pixel dimension.
Hope this helps deliver a better image results.
PS I use google images frequently and use the size feature quite a bit.
I might also propose searching images with a domain.
Also, how about offering users some curated image libraries. This could really make image searches much less flat.
Again, hope this helps.