[l10n] Welcome image in website screenshot gallery non-translatable and in English only

Hi,

I'm one of the Stellarium website translators (en-GB, la & sv), and have found a string that is indeed up for translation in the language file template, but not shown on the website. It's the string "Please select an image" that should be shown in the screen-shot gallery (e.g. in the Latin version: http://www.stellarium.org/la/screenshots.php), but instead is replaced by an image with the same text in English (http://www.stellarium.org/img/screenshots/placeholder.png).

This should be replaced by the string mentioned above, so that the entire website can be read in the language chosen by the user and also keep the language consistent throughout the pages of stellarium.org/*.

Regards,

Mikael Hiort af Ornäs
(lakritslemmel)