[Seaside] Create a personal banner for seaside

[Mike Hales]

Dario, in a workspace

ImageReader
      imageFromFile: (OpenFileDialog new select)
      toClass: YourComponentClass
      selector: #darioBanner

Will get you a CachedImage as a resource on the class side of
YourComponentClass (just select the jpg from the dialog).

Then to serve it through seaside (using the Canvas api) you can do
something like this:

YourComponentClass >> renderContentOn: html
html image
    resourceUrl: (
          html context
               urlForDocument: self class darioBanner image
asMIMEDocument content
		 mimeType: 'image/gif'
		 fileName: 'darioBanner.gif')