by Tim Hunt.
It is not clear to me where the links to these missing icons are coming from. Are they coming from the PHP code, or from content in the database?
In either case, you need to search and find the links, then you can eradicate them.
For the code, use grep, or any other full-text serach tool (e.g. the one built into your editor / IDE.)
For the database, a simple but crude approach is lots of queries with
... LIKE '%WaveLength%'
or something like that.
Also, I don't understand why missing images would completely break your layout.