A family of Microsoft word processing software products for creating web, email, and print documents.
Maybe too late, but I had the same problem. I had inserted a large 6600x5100 pixel black and white TIF image into a document and initially it was fine, but then all the images disappeared. So after reading through this forum I tried right clicking on the TIF image, selecting format image, and adjusted the brightness and contrast, and suddenly the image was visible, after adjusting the brightness and contrast back to 0%, I found all the images were visible again.
I was able to reproduce the problem by deleting the TIF and reinserting it either as a TIF or JPG. But this time the image wouldn't display, but the other images could be made to show by adjusting their brightness and resetting the image. But they would disappear again soon after.
I tried reducing the image size of the original TIF image to two thirds the size and one half the size and reinserting that and found no more problem with disappearing images. And just to double check I tried reinserting the original TIF image at the original size and the problem appeared again.
So... long story short, Word doesn't seem to like large pixel images (at least in my case), but seems to handle 4400x3400 pixel images. Bit of a pest if you want hi-res pictures for printing... Maybe someone else can see if they can replicate it?