Allocation of random photos to products

[andyramage]

We have just migrated to PS 1.7.6.8 from PS1.6 and I have spotted a problem with Products.

 When I do a product search by name the results often have a completely random thumbnail photo allocated.  This is also the image that appears on order confirmations.

However when I click on the product the correct photo appears and there is no trace of the randomly allocated and incorrect image.

This did happen in PS1.6 but it is much more prevalent in this version.

Anybody have any idea why this would happen?  Any help gratefully received:)

 

The attached screenshot shows a model of hat in 4 colours.  In two items we have a cap and a jacket instead of the relevant hat photo!  This is just one of many instances.