When I compare image and web, I can see that image searchers aren't counted as web searchers.
When I check positions, I can see that some search querries of one of my sites are at positions 1.1 to 1.9 based on web and 3.1 to 45.4 based on image search. Thats working - as long as it is picture search vs. web search. And as long as the search querry has no image-box.
Now your question - I checked another side wich has a lot of rankings in image boxes in web search. And I think you are right:
- Search Console is telling me I am on the web at postion 1.1
- When I Google it, my picture is the first one in a picture box at the top of the Results.
- Than there is a website (wich is not mine)
- And finally I am on Positon 2 (Picture Box, other Website, my Website)
- the same with a lot of querries. Google is here counting my image result (first result) in a picture box @ web search.
Tried to find some clients - found one. A search result he simply couldn't have with his website. But he had - it was a picture somewhere in the middle of the SERPs. I also saw that google seems to count each image as one result.
So finally you are right. If you have a Picture somewhere in an Image Box (wich is displayed in a Web Search) is a Web Search Position in Google Search Console.