Save the project as a folder and try exporting.
If it's already a folder, copy and paste it and try to export the newer one.
If that doesn't work, if you can pinpoint the image(s) missing from CocoonJS's compile, open them in photoshop/gimp/paint.net and re-save them.
If that doesn't work then it's something with the C2 CocoonJS compile or the code is causing issues with the compiler. Simpliest troubleshooting here is to use the copy that has the same issue, delete event sheets and have it start on a blank layout with all the assets on it and test that out, and if it crashes delete a couple them from the project until it stops crashing with CocoonJS.
If that doesn't work, then something is going seriously wrong with the exporter.
Also are you recrompressing the images or minifying the code?
My major issue is not being able to pinpoint exactly what the image cocoonJs is trying to referance.
All of the PNG's were re-saved with a batch export in photoshop (all are psd, exported as png.), and all of those were saved into the construct\textures\.. folder, and all of them were imported again into construct (opened object in animation window, imported each png again) The issue can not be with the PNG files, there is an event or layout that is trying to reference an image file that is no longer there or renamed, as the cocoonjs error refers to a null image reference. I do not get any such error on exe or html5 previews/export in any browser.
I have tried with both compression and no compression, and minifying and non minifying, these are not related.
Like you said, I am deleting layout by layout and testing on cocoonjs to try and narrow down what part of the game could be resulting in the error. If I can't isolate it to a layout, I'll do it with the event sheets. I just wish there was a cocoonjs log that shows what image was attempted to be loaded that yielded a null reference. I'm not sure there is something wrong with the exporter, it's most likely specific to my project as ashley has already responded telling me that it's a corrupt image in my project. I was hoping to get some feedback and suggestions on how to somehow more quickly hunt down the cause of the null image reference, as I am loosing a lot of development time to trial and error debugging.