New Post: Create Animated Gif with images of different dimensions

I'm building an animated gif using images of different dimensions. Example of code I'm using for each image added to the collection is below

img = New MagickImage(stream)
Dim geom As MagickGeometry = New MagickGeometry(500, 500)
geom.FillArea = True
img.Resize(geom)

With New MagickGeometry(500,500) I was hoping it would resize the image to a max width or height of 500 but it seems to ignore the width value and only uses the height value? Can you tell me what I'm doing wrong.

Thanks for your help