Need some MediaWiki help - evaluation in a template

[Labster]

Huh, let's see.  Elsif is really just syntatic sugar for another if/else block, so that's easy enough.

Code:

{{{image|
  {{#if: {{#pos:{{{image}}}|unavailable}}
   |<bgcolor=#CCC>[[File:{{{image}}}]]
   |[[File:{{{image}}}}]]
  }}
|[[Category:Page Needing Image]]}}}

Something like this maybe?  But you'd need to get support for pos from the admins I think:

All of these functions (len, pos, rpos, sub, replace, explode) are integrated from the StringFunctions extension, but are only available if an administrator sets $wgPFEnableStringFunctions = true; in LocalSettings.php.