He already did that, sorry for not posting the result here.
The urls are different.
VEF:
HTML Code:
<a href="http://imgbox.com/acsoujoC" target="_blank"><img src="http://t.imgbox.com/acsoujoC.jpg" alt="" onload="NcodeImageResizer.createOn(this);" border="0"></a> <br>
<a href="http://imgbox.com/admSutOP" target="_blank"><img src="http://t.imgbox.com/admSutOP.jpg" alt="" onload="NcodeImageResizer.createOn(this);" border="0"></a></div>
the other links:
HTML Code:
<a href="http://imgbox.com/ScOn42v9" target="_blank"><img src="http://t.imgbox.com/ScOn42v9.jpg" alt="" border="0"></a>
<a href="http://imgbox.com/rTvL9JGi" target="_blank"><img src="http://t.imgbox.com/rTvL9JGi.jpg" alt="" border="0"></a>
That explains the effect. But we still do not how the different urls were created in the first place. Browser or forum software should not be the cause.
I once noticed on imgbox that the links I got immediately after uploading were different from the ones I got later by clicking on share.
But that is not always the case. I checked some of my posts and the links I get from imgbox now are the same I got after uploading. Maybe imgbox has some background process that detects duplicates, removes them and hands out the link to the original in future. But that is just guessing, we will never know how the internals work.
So this is still partly a mystery.