An issue is that there doesn't appear to be a page/object which points to the glow images.

I'm not sure if this will help your issue, but you can certainly experiment with this, if you really can be bothered - it involves some hex editing.
This will cause multiple icons to point to one bit of icon data - will reduce the size of the RCO, but may not help the memory issue.
Also note that after you do this, you will no longer be able to edit icons with RCO Editor, as RCO Editor only updates icon indexes for the icon being edited.

Okay then, start RCO Editor in expert mode (you may need to edit the INI file).
Now you'll need to dummy all but one of the glow images.  Select the glow image that you didn't dummy, and record the Entry at value.  Add 0x2C to the number - remember this address for now.  Open the RCO in your hex editor, and go to the address you just calculated.  Record down the next 12 bytes of data.
For example, if the Entry at value for the non-dummied glow image is 0x74C, adding 0x2C gives 0x778.  Going to 0x778 in a hex editor, you would record down (or Ctrl+C) the contents for the data in the range 0x778 to 0x783, inclusive (12 bytes).

Now, here comes the repetitive part.  Go to the first glow image you dummied.  Grab the Entry at value for that icon.  Add 0x2C again to this number, and visit that location in the hex editor.  Overwrite the next 12 bytes with the 12 bytes that you recorded (or copied) earlier.  This effectively redirects the image entry to the data of another image.
To confirm you've done it all correctly, reload the RCO in RCO Editor, and check the original non-dummied glow image, and the dummied glow image that you just redirected.  If everything is done correctly, they should both show the same image, and have the same Data at value.

You will now need to repeat the above (from "Now, here comes the repetitive part") for each dummied glow image.
Since this may take a while, I'd try dummying a few first before doing the whole lot.

Good luck!

(This post was last modified: 19/01/2008 05:34 AM by ZiNgA BuRgA.)