Problem with Brandon Kelly's Field Frame + Ngen File + Lumis' Img Sizer

I’m using Brandon Kelly’s Field Frame + Ngen File + Lumis’ Img Sizer to display an image. I want to use Img Sizer in case my client doesn’t upload the right image size.

I’m using field frame with FF Matrix to upload the images so that a description can be input for use in the alt tag. The FF Matrix loop is working just fine, but the image does not display when I add the img sizer code.

Here’s what I have:

{cover-art-dt}
{exp:imgsizer:size src="{image}" width="100" alt="{description}"}
{/cover-art-dt}

I’ve noticed that other people have passed the img sizer code inside a FF Matrix tag pair. I’m not sure what I’m doing wrong. I tried using an img sizer tag pair and this didn’t work either.