I've compressed a lot of pngs using a web optimised palette. When these are saved in word whether as .doc or html the images are increased in size eg from 12kb to 99kb. The only work around I can think of is to manually rename all original images (to match words names) and put them into the associated html folder in place of the corrupted images. Any tips much appreciated.

Looking at the compressed pngs viewed with HEX-editor plugin for Notepad++ showed that the 'critical chunks' that define pixel dimensions and pallet (https://en.wikipedia.org/wiki/Portable_Network_Graphics) IHDR and PLTE are missing. So nothing really to do with Word-using another compression program solved the problem.