I think I finally got myself straighten out. After about a gazillion edits, you can view my final-form April 4th post here: http://markarmstrongillustration.wordpress.com
FWIW: I found I had better luck if I stuck with the Visual Editor, wrote the text and inserted images, and then fine-tuned the images' appearance at the end, as follows:
1. While in the Visual Editor: Click on the image to be edited
2. Click on the Mountain Icon indicating you wish to edit the image, not delete it
3. In the pop-up window, click on Advanced Settings
4. If you want a border around the image, enter desired #pixels in the Border Field
5. To add space above and below the image, enter desired #pixels in Vertical Space
(***note: this adds an equal amount of vertical space above and below the image,
but you can edit the image again (Steps #1-3 above) and adjust the #pixels
above and/or below the image by entering the desired pixel value in the Styles
field; repeat this edit as often as it takes to position the image with the desired
amount of vertical space (pixels) both above and below it)
Other Tips:
1. Align the image when you first insert it-- makes life easier. However, you can still
do it after the fact by doing Steps #1-2 above, then entering the desired alignment
in the Edit Image pop-up window.
2. Resist the temptation to resize your image in Edit Image pop-up window
(90%, 80%, whatever); it works, but you'll be resizing a JPEG or a GIF, and
you'll wind up with a degraded image. If you decide your image is too big, delete
it, create a new one (in Photoshop, whatever), and upload the new image to your
WordPress Media library.