"See Also" with images

I’m still just evaluating DEVONthink and one of the things I’m trying is how useful it is for managing photos. The manual says DT can be used to “search for similar images using an image example”. Yet in my experiments so far, the behavior of See Also with images is bizarre – in fact it looks completely random.

Here’s what I did: I created a “Photos” group in DT and loaded 32 photos into it. I made comments about each in the Information window using words to describe the subject matter, color, and composition. Then I selected one image at a time and clicked See Also to see what it would turn up. Puzzled by the results, I split the photos out into a half dozen sub-groups organized by subject matter and tried See Also again, with no improvement.

I expected the See Also with images to use the comments to match landscapes with landscapes, faces with faces, reds with reds, etc. But so far I see no pattern to the matches. In fact, the #1 match will often share no keywords at all with the photo I’m matching.

What gives? Is the problem that 32 images is too small a sample? (I’d expect the See Also function to be less than stellar for a collection of that size but not for it to match images with zero terms in common.) How many would I need for an adequate test? Has anybody else used DT as an image library with success?


– Prentiss Riddle prentissriddle.com

Hi Prentiss,

I was amazed by this claim in the Manual for DT, too.

I tried it, as you did. But as far as I can tell it’s “baloney”. I showed it to my son who works for a research arm of a global image/camera/document-processing company and who writes image management software.

Alas, his answer was a snort and a shake of the head. He no longer finds it necessary to vocalize the ‘how dumb are you?’ question.


Unfortunately the manual is very outdated. DT had image searching as described above back in version 1.8 which is when I started using DT, but it was dropped in 1.9 – to my chagrin, and others. After some requests for it again on the forums the developers have promised to bring it back in the near future… but it’s still not in 1.9.2. It used to be it’s own pane in the search window, and you could paste in an image and it would search for similar images. I had not used it extensively but it did seem to work to some degree and was one of the things that first made DT stand out to me above other text-only apps. If and when it returns I plan to try to make use of it. But for now, it’s still gone… so don’t waste your time on anymore experiments until they bring it back.

Why did they drop it? I can see great potential in such a feature.


Moses: Thanks for the background. How did it do image matching? Was it by color, shape, or what?

How did you find it useful? I’ve heard about such searches before but frankly haven’t been able to imagine what they’d be good for until they’re so sophisticated that they can recognize faces, objects, locations, and other such constructs from the human mind.

And do you have a guess as to why my results from text matching of images were so bad? Is it simply that DT’s matching algorithm breaks down entirely for such small collections and/or small amounts of text?

– Prentiss Riddle prentissriddle.com

Sorry, I can’t answer those questions. The developers will need to answer themselves as to why it was dropped. As for how good it was at matching I can’t really say as I did not use it that much. I had only played with it for about 15 minutes, but had intended to get back to it later… then it was dropped. Regarding current matching, my guess is that matching algorithm doesn’t look at metadata in comments, but again, the developers or someone more in the know will need to respond to this. I just wanted you to know that the feature had been there and that the manual had not been revised. Like you, I hope it does have a future in DT though.

Because not many people used it and because it was very basic. We may reintroduce it in a later release, but with a more sophisticated algorithm.