Hi Sergiy...
Not sure what you mean by this number "1259 - 1040". There is no such resolution as that. And i hope you didn't create your Website to that number. [stuned]
In general, the majority of users will have an 800x600 pixel screen resolution. Most folks into graphics will usually have at least one step higher than that -- 1024x768 (
talking PC, not Mac. Mac is slightly smaller ).
The monitor size
will make a little bit of difference as to how a Website is seen, but not a whole lot; especially if you apply some good design rules like "less is more", and keeping the text size to a legible level, but not huge. Page layout can also make a big difference in this situation Sergiy.
Bear in mind too that when i say 800x600 that doesn't mean your content can take up that much room. 760pixels is the widest you'll want to go with your table widths. This allows for the browser's borders and scrollbar.
If you need more specific info on this i suggest you search on this topic -- Website Design specifications. There are some general rules/guidelines that you need to apply. And there are some good sites around with all this info on them. Try this one:
www.w3schools.com/html/.
::: EDIT :::
hahaha [bustagut] geeez guys! I left for 5 minutes and everyone snuck in before me! hehe DOH! [doh]