implementing flow control in bash

[Tony Zanella]

Hello all,
I'm sure this isn't a bug, but just my inability to wrap my head
around enough of bash flow control:
I wrote the following shell script to find all gifs in a directory.
Then use "identify" from imagemagick to grab the gif width. Then,
print the image name and width to a file.

  for i in `find . -name \*gif`; do identify -format "$i %w" $i; done
> results.txt

Then, I used a ruby script to cull only those images with a width over
570 pixels. So, problem solved, but I wanted to see if I could do it
all in bash.
More specifically, (if this makes sense) I want to "do identify
-format "$i %w" $i" only for those "$i %w" where "%w" is > 570.

The above script will give me output like:

  image1.gif 360
  image2.gif 780

But I want it to give me:

  image1.gif 360

In pseudo-code, I want something like:

  for i in `find . -name \*gif`; do identify -format "$i %w" $i if [%w
> 570]; done > results.txt

Any suggestions?
Tony