TYPO3 Core

But then this issue affects TYPO3 4.3.10, correct?

yes

I got also an error with showpic is involved:
Core: Error handler (FE): PHP Warning: implode() [<a href='function.implode'>function.implode</a>]: Argument must be an array in /home/.../typo3_src-4.4.6/typo3/sysext/cms/tslib/showpic.php line 152

Its just a warning I found in "Admin Tools->Log" in 4.4.6

This warning overfloods my error log too -> 4.4.6

Hope there will be a workaround soon

Same Warnings in "Admin Tools->Log" since v4.4.5/6
Only for FE.
All is working fine (Scaling, effects, etc. both in FE & BE). Can't really reproduce it self.
A search in access-log resumes, that only web-robots produce this error, while GET with missing params like '&parameters[n]'. Seems that bot's get links by JS openPic with oldWay style-parameters (&width=..&height=..&bodyTag=), wich doesnt worx, since showpic.php need commited md5-parameters for styling.

committed v2

trunk, in rev. 10531
TYPO3_4-5 in rev. 10530
TYPO3_4-4 in rev. 10532

This still floods my sys log in TYPO3 4.5.3. Any suggestions?

I was able to get rid of this problem by adding this to my htaccess:

RewriteCond %{QUERY_STRING} eID=tx_cms_showpic
RewriteRule ^ %{REQUEST_URI}? [R=301]

The RewriteCond in htaccess lead to disabling the clickenlarge-Feature for pictures in the text, which I need.
The problem still persists in Typo3 4.5.8.

Therefore I had another try with robots.txt:

User-agent: * 
Disallow: /typo3/ 
Disallow: /showpic.php

There are some people working on this problem and sharing experiences in a German forum: http://www.typo3forum.net/forum/typo3-4-x-installation-updates/53163-core-exception-handler-web-showpic-php-line-173-a.html

I think it would be better if this error returned a 404 HTTP status code, as described here: http://www.typo3-nürnberg.de/typo/konfiguration/fehlerseite/ (page in German, see "Fehler und cms_showpic")

Returning 500 will cause the search engines to assume, that it is a temporary server error.

404 is more clear: the page for this URL was not found / does not exist.

Adding showpic.php to robots.txt will cause the pages to no longer being crawled, but will not necessarily remove it from the index (documentation is a little unclear here, search engines may behave differently).

In my opinion, a Oops, a 404 HTTP status code would be much better than 500. Because it's not a server error, but the URL is malformed and will never return a valid result. So it's a 404.