{getImageDimensions image = $tmpImages[0]} error

[criocere]

Still trying to migrate from v4 to v5...
I try also to use extensions for tags and modifiers

This line is ok in smarty v4
{getImageDimensions image = $tmpImages[0]}

But in smarty v5 I get
Got error 'PHP message: PHP Fatal error: Uncaught --> Smarty Compiler: Syntax error in template "file:zzzzPage.tpl" on line 235 "{getImageDimensions image = $tmpImages[0]}" unknown tag 'getImageDimensions'

If I modify my line like this (adding a blank after the first bracket), it becomes ok
{ getImageDimensions image = $tmpImages[0]}