Does Sitespinner Pro enable you to change a white background in a picture to transparent? Thank you for your time.
SS cannot change the background color to transparent, but it does provide a way to turn a color transparent. If you select your image, then open the Shading Editor to the Fill Settings tab, you will see a check box labeled "Transparency Mapping". If you check this option, you can use the eye dropper tool to select a single color in your image than will be converted to an alpha transparency channel. This could produce some side-effects; selecting the background color will also convert that color if it is used in the image subject. For example, if you have a portrait with a white background, not only will the background change to transparent, but also the whites of the eyes in the portrait.
This does not work well with text. Most text in an image uses anti-alias so the text characters can appear "rounded" and not pixelated. Anti-alias will use the background color of the text and mix it with the text color to fool your eye. So selecting the background color and making it transparent will not convert the anti-alias color (which is a shade of the background color and not the true background color). This means you will end up with artifacts around the image text.
Also, transparency mapping only works for images that support an alpha channel, such a GIF or PNG-32 (PNG-8 is iffy). It does not work with JPG images.