Image resizing in RSS feed

[Actron]

I have following problem:
When I add an RSS feed I can't resize the image. For example:

Image in RSS feed:
https://de.web.img3.acsta.net/pictur...59/5371074.jpg

RSS feed:

[center][imgi]{feed:enclosure_href}[/imgi]
[SIZE=20px][COLOR=red][B]{feed:title}[/B][/COLOR][/SIZE]
{feed:description}[/center]

I try it with a custom bbcode:
Tag: imgi

<img src="{param}" height="600">

It doesn't work.

I try also:

[center]<img src="{feed:enclosure_href}" height="600">
[SIZE=20px][COLOR=red][B]{feed:title}[/B][/COLOR][/SIZE]
{feed:description}[/center]

What is the problem?