Indesign has got a very good mechanism of spotting and warning broken links. Is there a mechanism where InDesign can automatically light up pics that are below a certain range of dpi?
Not really.... You can set up error warnings, but nothing will present the "application stopping" alert warning similar to missing links.
You could manually select each image and then use either the
Links Panel to check each linked image's PPI.
You can also use the Preflight panel in InDesign. (Window > Output > Preflight)
You have to set up a Profile for Preflight (Using the panel menu
There you can set conditions which will create an "error".
Once it's configured, you just need to watch the Preflight Panel. If there's a problem, it'll be listed there...
For print, you can also export to PDF and then run the Preflight tools in Acrobat to verify the PDF meets the standards desired. But that's external and not really part of InDesign directly.
But ultimately, there's nothing that is application-pausing with front most alert forcing you to click cancel or OK before moving on the same way missing/broken images present an alert.