1. How big is the file?
2. 32 bit or 64 bit OS?

If I remember correctly, I'd get this with WD9 on a 32 bit machine when the file had a LOT of photos and the file size got up around 33/35MB (or maybe it was 43 to 45MB???; too many years ago!). ALSO - watch the size of photos - - - these can make for huge file sizes and eat up memory on a 32 bit machine. PNG files can be a lot larger than a JPG, so be careful with these and their size. As previously mentioned, optimize your photos and save.

TIP - save FREQUENTLY. Here's a suggestion/technique - Use a different file name such as "ABC_WEBSITE_2015-12-18_V001" and each time you go to save, increment the "v001" to "v002", etc. When you go back to work on this website on another day, change both the date and reset the version to "v000" which means this is a new day, and v000 means it is a direct copy from the previous day, and no changes as yet have been made. This helps recover with very minimal loss when something goes wrong. Periodically you can purge the unnecessary versions.