Dating a picture

[Coco]

Can anyone help to date a picture, please, perhaps by dating the use of square tacks - no head to speak of - a little less than an inch long - pointed on one end --used to hold parts of a picture frame and the wood backing together. Not to hold the picture frame together though. Dark in color.

[mikewith]

All but impossible, however well you describe the tacks. Not to mention woprking out whether the tacks are as old as the painting. This is surely one where you actually have to take the picture to an expert (or bring the expert to the picture) rather than relying on the web. Sorry I can't be of more help.