How to convert HTML to JPG with Coldfusion (or other way)?

If you're on ColdFusion 8, you can use the <cfimage> tag to do what you need.

I am on CF8, can you point me in the right direction please for what I need?

It depends on what you are converting.  But since it is html, this blog entry might work well for you:

http://www.coldfusionjedi.com/index.cfm/2007/7/30/ColdFusion-8-Working-with-PDFs-Part-8
source: http://forums.devshed.com/coldfusion-development-84/thumbnail-of-any-file-format-in-cf-599710.html

These links appear to be making thumbnails from pdfs, I will look into cfimage to see what I can do.

Yes, but you may be misunderstanding.  They convert html to a pdf variable, then convert it to a jpg.  You can of course use cfimage, but cfimage cannot handle html.  That is why you may be better off using the technique in the links. It is far easier to handle html (<b>, <h1>, etc...) with cfdocument.

... of course if you just want to draw plain text on an image, then yes .. you should just use cfimage.

I just tested that, and it would work great, actually. Is there a way to save as JPG and save to a particular file?

Sure.  Either use the ImageWrite(..) function or the cfimage tag to save the image to disk:

<cfset img = ImageNew("", 275, 60, "argb")>
... other code
<cfset ImageDrawText(img, "Something!", 85, 50, fontProp)>
<cfset ImageWrite(img, "c:\whateverPathYouWant\theImageNameYouWant.jpg")>

This is brilliant. One more thing - can I set the background color? perhaps by drawing a square the size of the image?

Yes. Background color is one of the parameters for the ImageNew(..) function.  Just use any hex color.

<cfset img = ImageNew([source, width, height, imageType, canvasColor])> .... ie
<cfset img = ImageNew("", 275, 60, "argb", "FFFFFF")>

http://livedocs.adobe.com/coldfusion/8/htmldocs/functions_h-im_34.html#5179132