TinyMCE
It's best to use TinyMCE's image editing functions to resize an image rather than the "Width" and "Height" properties in the Appearance tab. If you use TinyMCE to resize the images, they will actually be resized on the server. If you use the width and height properties in Appearance, they will be transmitted to the web browser at full size (slow load) and then resized on the fly by the web browser.
You can resize images in TinyMCE like this:
1) From the visual editor, right-click the image you want to resize. Choose "Insert/Edit Image".
2) Click the Browse button to the right of the image's path
3) Find the image in the list of images.
4) Click the upward-facing arrow in the lower right hand corner of the image's thumbnail. This brings up a menu; select "Edit".
5) Once the image loads, click the Resize button
6) Enter a new width or height. The other dimension will change automatically to preserve the image's ratio if you leave "Constrain proportions" checked.
7) Click Save. Leave the file name as it is or give it a new name if you want to preserve the larger version.
8) Click the close box on the image editing window.
9) Find the thumbnail of your smaller image. If you renamed it when saving, be sure to select the image with the new name, not the old one.
10) Click the thumbnail to select it for placement.
11) Click Insert or Update.
