Get Before Character

[FrederickGeek8]

I'm trying to parse bbcode and there is this special img tag that allows width and height and comes in this format:
[syntax=text][img=500x300][/img][/syntax]
How can I take 500x300 and split the string into 500 and 300? (two separate string)

Right now I have this but the number 500 and 300 for some reason are not included in the output string.
[syntax=php]"<img style='height:".strstr("$1", 'x', true).";width:".strstr("$1", 'x').";' src=\"$2\" />"[/syntax]

preg_split also doesn't work. The first index of the array just contains the full string

[Temor]

the first thing that comes to mind would be to explode on x and remove the first 5 letters of the first index ( [img= ) and the last character in the second index ( ] ). But that might not work with what you have set up.