There is no good answer to the question. Other than, if you do not want your image to be stolen, then do not put it on the web.
Your image size of 4300x2900 pixels will show (as large as) 4300x2900 pixels.
Most monitors are not larger than say 1920x1080 or 1680x1050 pixels, so this is much larger than needed to show on the web.
The only reason for the larger images would be to print them. Video screens are not that large. Video applications (web browsers and photo editors) resample a temp copy of the big images smaller to be able to show them on the smaller video screen.
4300x2900 pixels would print 14.3x9.7 inches at 300 dpi (and half again larger at 200 dpi)
So if you do not want them printed, don't do that. Instead resample and upload smaller images, more web screen size.
For example, THIS web site does not like them to be larger than 1024 pixels wide.
Setting them to say 72 dpi does absolutely nothing except to change that one number. Anyone can change it back, same as you changed it.
If they are still 4300x2900 pixels, anyone can still print them at 300 dpi.
Any one can upload it to Walmart and specify to print it 8x10 inches (at whatever dpi it computes that size).
Your only defense is to upload smaller image size (pixels), too small to print. Like maybe 1024 pixels width.
But even 1024 pixels will still print 6 inches size at 170 dpi.
