SEO weights of image attributes: any recent experiments in this area?

When searched in Image Search, what's the relative weight of each of those characteristics?

An image on a page can be characterized by:

(I added numbering to the list, so we can refer to each item later)

GKA-1 filename (img url)
GKA-2 alt
GKA-3 title
GKA-4 text around it
GKA-5 page title
GKA-6 page H1
GKA-7 anchor text in links pointing to the page

Added by +Lyndon NA  :
LNA-1 Dimensions
LNA-2 FileSize
LNA-3 Quality/DPI
LNA-4 Quality/Loss
LNA-5 Uniqueness
LNA-6 Load speed
LNA-7 Comparison of the above to other "similar" images

Added by +Bill Slawski  :
BSL-1 Text - OCR'ed within an image, such as a street sign, a logo on a car
BSL-2 A person's face - through facial recognition
BSL-3 A location or landmark - through a visual query
BSL-4 One or more textual tags, as indicated through a similarity search result with a known image that has been tagged.
BSL-5 Caption
BSL-6 Volume of clicks on an image for specific queries in search results.
BSL-7 Colorfulness
BSL-8 Width to height ratio
BSL-9 Face photo vs. photo vs. computer graphic
BSL-10 Contrast within the image
BSL-11 Blurriness within the image
BSL-12 Size of the image
BSL-13 Relative position within a web page
BSL-14 Relative size within a web page
BSL-15 Relative vertical position within a web page
BSL-16 Relative horizontal position within a web page
BSL-17 Frequency of usage on a site
BSL-18 Frequency of usage on different pages of a site
BSL-19 Text associated with links to an image
BSL-20 Number of sites that contain similar images
BSL-21 Link relationships between images (thumbnails, images near each other that share associated text)

- anything else?

Thank you!
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