I know that there is a option to limit voting for one image only but Is there a way we could assign a voter to vote only up to 3 images in a poll?
Our poll maker allows various voting types which also includes Dot Voting. Here you can define how many votes each voter can cast and how many votes a single option may receive per voter. So in your use case each voter has three dots and each image may receive one dot per voter.
You find this in the first step when creating a photo contest.