You have a puzzle that you wish to lay out on the table. It is not the weight of the puzzle that is causing the problem, but rather the overall length and width that is too large. No matter how strong the legs are, they can not compensate for or support the puzzle which is too large for the table top itself.
As you can see by the chart below, it is not the file size that contributes to this problem, but rather the pixel size.
We have found that Photo Magic, MS Paint, IE, and Firefox all appear to have the same size limit. Of the ones that we have tried, only MS Photo Editor is different. We tested three different charts within various programs and below we have shown the maximum sizes of each that would open without going to a black screen.
Using Micrografx Photo Magic, Mozilla Firefox, Internet Explorer, Microsoft Paint
Using Microsoft Photo Editor
Unfortunately this is due to the size limitations of the program you are using to open this file. Various developers make certain assumptions about "reasonable" image sizes, and about what "typical" users might want to create. They then limit their program so as to not exceed the system's resources.
You may wish to look into finding a program that can handle the larger charts or you may want to break your charts down by showing only portions of your tree at a time.