I see that Seliah wants to know more about the inner workings of the,

'max 4096 characters, x-number left' ... in the comments section

i can't be certain ... but I'll try to give you an educated guess ... so if it turns
out that I'm wrong ... please don't hit me ... just kidding. 

That having been said, I did a little 'research' using your most recent upload ...
"Snapshots in Time 11- Ghosts of the Past" as the test case ... yes, I know that
in statistics, that would be called "small sample size".  [grin]

Methodology

I looked at the comments text as displayed and also the portion of the comments
text in the html coding for that image.  In both of those 2 observations, I copied the
'sample' into TextPad (TextPad is a very good, very flexible plain text editor that I
have been using for about 10 years).  TextPad has the ability to show me the word
and character count of a text document.  

Observations

Text as displayed     4014 characters      file size 4068 characters

HTML selection         4243 characters      file size 4203 characters

Analysis

The reason for the difference between displayed text vs. the HTML coding is
that there are some html tags that need to be generated for each paragraph
of your comments. 

The reason for the difference between the character count and the file size is
due to the number of lines in the scrap of text in the TextPad buffer... you see, 
each line of text has 2 control characters (CR and LF) to indicate the end of the
line ... TextPad shows me the number of characters and also the number of
characters plus the number of CR+LF characters. 

Conclusion

I suspect that while typing, some local java script code is counting the characters
you type into a buffer in your local PC ... but when you submit what you entered,
some code on the renderosity server parses your comment into HTML code (that 
program adds whatever HTML tags are needed) counts that expanded number
of characters against the 4096 limit. 

Advice

Type the comments into a text editor such as (TextPad) and check the number of
characters you typed ... in TextPad, that would be "View" -> "Document Properties". 
In TextPad you can know the number of lines by using Crtl+End to place the cursor
at the end of your text.  Multiply the number of lines by 4 and add that to the file size
characters ... if that is over 4096, you will probably have a problem when you submit. 

HTH ... but always remember that YMMV ...

--
Martin
p.s. TextPad can also spell check.