- Not a direct solution. But I use it for "storing & forgetting". Their menu bar app allows searching by name, contents, text or color. Again, might not work for you in some cases.
- I use Raindrop chrome extension, and they have a mac app as well. Maybe a little bit overkill on what you're looking for, also there's Google Bookmark manager if you want an even simpler approach to image bookmarking, not entirely saving images, but just bookmarking.
I used to use Stache for my bookmarks before d3i abandoned the product (despite being paid). Stache was amazing for a couple reasons: when you bookmarked a webpage they captured the HTML and a really good full-page screenshot. They used the HTML to search and to render a preview of the page later if you were offline, and the screenshot was used for a thumbnail and to let you view the page as it was when you captured it, even if it changed or died since then. Alas, syncing broke in Stache a couple years ago and I switched over to Raindrop.
Raindrop initially had new features coming out frequently. It seemed like they were going to grow fast and start charging money once they had a healthy user base in order to hire on additional people. They did grow fast, but I think the single developer lost interest in developing it so the product stagnated and a traditional support channel never materialized. They did add a paid subscription, but with a modest additional featureset.
Most unfortunately, Raindrop has failed to figure out how to properly capture and resurface bookmarked pages. Thumbnails are often a small icon from the page blown up into pixelated oblivion and then cropped square. There is a feature to capture a screenshot of a page, but there's zero UI feedback once you opt into it on a given bookmark and it frequently doesn't work. Search is even worse: results are sorted by recency, there isn't an option to use relevancy, and Raindrop doesn't capture page content so only the page title and description are searched. Tags aren't even searched unless you specifically add the hash symbol, making the benefits of tagging limited.
I'm sure something else will come along and replace Raindrop for me eventually, but for now, I'll continue amassing useful links in an utterly unsearchable form in hopes that they'll suddenly become useful one day.
I've used this pretty much since it first launched and I really love this app, I use it frequently throughout my day on all my devices. I love that I am able to have various collections, customize them and just really keep my bookmarks synced across devices. It's a handy and very useful app, I highly recommend it.