# Image Verification (Raw not DNG)



## Linwood Ferguson (Jun 16, 2013)

The new LR5 feature for mass DNG verification prompts me to ask again... 

Is there a plugin or feature that allows one to confirm that stored images have not changed.

I am currently using ImageVerifier for that (link) but it is old, not actively supported, and quirky.  And it's outside of Lightroom.

There are two parts of this really: 

1) Validation -- are the image files valid, and 
2) Verification they have not changed since the last check

I'm not nearly as interested in the validation as in the "did anything change".  As you upgrade PC's, copy files between disks, etc. there's always a chance you corrupt a 5 year old image and don't notice until 3 years later -- after which you may or may not have original backups, much less all your edits (ok, LR edits would be in the catalog, but not external plugins).

Currently what I do is run an ImageVerifier pass about once a quarter to see that old images remain unchanged, and also to calculate checksums on any new photos.

What I really want to do is have Lightroom calculate the checksum, stuff it in metadata, and on request recalculate and compare.  And calculate it initially on ingestion. 

It's a lot like the DNG checksums.  

I am thinking of trying to write a plugin to do so, but it seems like such a simple need -- does something like this already exist?


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## Mark Sirota (Jun 17, 2013)

I like the idea of a plug-in to do this. I have a homegrown tool that does it -- after the initial import I calculate a checksum, then I confirm the checksum periodically on every copy.  There's really no reason I can think of that a plug-in couldn't do this.

If you write this, I'd be willing to be a tester.  If you choose not to, and if none of the likely candidates reading this forum choose to pick up the idea, I'd be willing to shop it around to some of my contacts.


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## Linwood Ferguson (Jun 17, 2013)

I'd like to write one, not sure if I have the time to figure out lua and the LR framework.  Let's see how the week develops.  The SDK has some pretty complete examples, including one to add metadata (needed to store the checksum).  I took a brief look, and the things that weren't obvious were: hooks on import (explicit and implicit such as Edit In) so you can calculate a new checksum on a new photo without user involvement, a fast way to calculate a checksum on a file (there's an MD5 for string function, not sure if you can load a file into a string). What I was thinking it would do is have a good/bad status in metadata, then allow it to run in background setting that flag, and you could use something like a smart collection to actually see the results (as opposed to having it tie up your UI while it ran, since for large collections it may take hours).  But I work full time and photos are a hobby, so not sure I have time for the learning curve (I couldn't spell lua before this weekend).


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