Right now... if you drag the corner or side of an image, it expands the image in both directions at the same time.
Which is fine if your are simply resizing it on the screen.
But if you are layering a colored image over it's BW counterpart (for fill in effect), or trying to hide an object by enlarging a white (or same color as the background) block over it... this becomes problematic.
With any my graphic programs, if you have a square, and you drag the upper right corner to enlarge it, the bottom left corner "stays put".
If you drag the R side to widen it... the L side stays put.
You drag the right upper corner and the left lower corner moves in the opposite direction at the same time.
Trying to size one image directly on top of a second image (or getting a box to cover an specific portion of an image) means enlarge a little, move the image, enlarge the image some more... move it a little more... etc...
Again... open up a graphics program.
Draw a box
Draw a second smaller box
Move the smaller box so the bottom left corners match up
Then drag the upper right corner of the box and you can easily size to small box to the exact same size as the larger box, because the Left corner stays put.
Trying do to that with VideoScribe is a mess, because both ends of the picture you are enlarging move at the same time.
If you have two images perfectly aligned with the same center point, select them both, then scale them both at the same time.
If your two images do not import perfectly aligned with the same center point, then open your vector file, add a 0% opacity ellipse path that surrounds all of the other paths, then save your color version and your black and white version, each with the ellipse. Both images should now import perfectly aligned.
In general you do not need two files for color reveals.
There are reasons to have a center line traced SVG to draw first, then have a JPG to color in.
I put screenshots on this post:
Posted information in the thread at the link you provided.