Reading Div Width - For Same Div Element ?

I have problem with reading div width, sometimes, for this same div element, jquery returns width of 800 (which is correct), but then sometimes, it returns 93(which is not correct).

Here's the html (part of it):

Code:

And here jquery function:

Code:

This line is the problem. Sometimes, it says width of that div element is 800, sometimes 93. I put border around div, and i can clearly see it really hs width of 800, but sometimes, i still says (firebug) that width is 93. there is the image inside this div.