ImageData restore problems

[FlexibleLearning.com]

I have an embedded image, size 120Kb, and want to toggle between a
non-compacted (120Kb) and a compacted (30Kb) thumbnail version...

1. I thumbnail the original image (data is still 120Kb as expected).
2. I store the TEXT of the resized image.
3. I compact the image by setting the imageData of the image to the
imagedata of the image. The size reduces to 30Kb as expected.
4. I restore the saved binary data.
Result: A blank image

1. I thumbnail the original image (data is still 120Kb as expected).
2. I store the IMAGEDATA of the resized image.
3. I compact the image by setting the imageData of the image to the
imagedata of the image. The size reduces to 30Kb as expected.
4. I restore the saved ImageData.
Result: 30kb, not 120Kb

Question:
What must I store in Step 2 above in order to re-instate the 120Kb data in
the thumbnail?

Baffled and a tad frustrated.

Hugh Senior
FLCo