Hi pastime,
I have never checked google images when searching for mine, or any other, ebid ads. I've only ever searched GS ads. What you say seems to confirm what I found -- regular clicking and viewing will increase the number of your ads. GS will show in its search results.
Are you also saying that you're seeing your shop name on the side-bar as "Ebid - pastime Vintage Collectables" for some of your searches?. If so that also seems to confirm what I found, that regular viewing does get Ebid + seller name added to the side-bar. If you tell me what you were searching for, I'll do the same search and hopefully will be able to confirm that Ebid has been added to another set of search results.
Although I can always see some of my (about 200) Art Deco ads. on GS, I've never been able to find all of them at one time, even if I tick the Ebid - theElench box. GS does rotate what it shows, sometimes one of my ads. can be seen for weeks, but others come and go in a few days. It seems to me to be quite random. But every ebid ad. has the "See Other Items" button giving the viewing shopper the opportunity to see all of the sellers' ads. whether they are showing on GS search results or not.
Sorry, I can't help with tips about Pintrest, I've never used it to PIN images onto Google and likewise with the other SM sites you mention. Perhaps others who do use them might have some ideas?
Hope this helps. I think that just the fact that there are now two ebid sellers clicking their ads. regularly will (possibly) raise ebids visibility on GS, both as a site and by increasing the number of visible ads. shown to shoppers.