When I first started writing I assumed that Google saw images the same way as we do, but they don't. Search engines see what are called alt-tags, alt-tags are basically words that describe the image and are another way to get keywords onto your lens.
There are two ways in which you can add alt-tags on Squidoo and they depend on how you upload your photographs.
The first way is when you upload your image from your computer into a Text Module, Text Module with Big Picture or a Polaroid Module - when you're uploading it the box will look like this -
The first box is where you choose your file from the computer to upload, the second box is called Label this photo and the third box is the option to link the file to a url. The label this photo is where you add your alt text.
This alt-text should include some keywords in it, but if my image uploads in a big enough version to read it (I haven't done a screen print on blogger since the changes) then you'll see that I didn't use the words Lady Gaga Tattoos on this photo despite that fact that it's on my Lady Gaga Tattoo lens and there's a reason for this. You need to vary the keywords used on your images the same as you do in your text or Google will think you're keyword stuffing.
I did a lens over a year ago now and had just been reminded about the importance of alt-tags so I went through and updated all of the products with the same title - my main keywords. It did not work and despite the fact that lots of people were searching for these exact keywords and I actually promoted the lens a bit it was getting nowhere. I recently reviewed the lens wondering what to do and I noticed the alt-tags and banged my head on the desk - what was I thinking??? Needless to say I have altered them know so that it doesn't look like such a spammy page in Google's eyes - to read it you actually don't see a lot of keywords, because you see the images as images, but to Google it would've reeked of spam (I should have known better).
The second way of adding alt-tags is when you're using images via HTML either because you're hosting them elsewhere or because you're using products with an affiliate link like Zazzle or Shareasale. When using affiliate links they will sometimes contain alt-tags already, but they may not be the tags you want to use so it's easy to change them.
<a href="http://www.shareasale.com/r.cfm?u=272258&b=82823&m=12853&afftrack=gothic%20count%20costume&urllink=www%2Ehalloweenmart%2Ecom%2Fadult%2Dcostumes%2Fgothic%2FCount%2DGothic%2Ehtml"><img src="http://www.halloweenmart.com/core/media/media.nl?id=57955&c=801044&h=52b96c0c24e7488cff1f" alt="gothic count costume" width="190" /></a>
The alt-tag is showed in red from an affiliate code I got from Shareasale - the first part of the code is the linking part shown inside the <a> tags and then you have the part which shows the image - immediately after the image url (which is always inside "") you simply put the alt tags like above.
Now I actually altered the words inside of the alt tag in this code as I was doing a blog post on Gothic Costumes and wanted to use the words Gothic and Costume in there for more keyword juice. I notice especially with Zazzle that the alt tags aren't always the best for your particular lens so feel free to change them to something that fits better.
Changing alt-tags - now it is easy to change your alt-tags at anytime, simply alter the HTML if that's how you've uploaded the image or go in to edit the module and change the Label this Photo box. Now when you change the label you must remember to hit upload again or the change will not happen. You will get an error message, but just ignore this (it seems to happen whenever you don't change the image itself, but just change the alt tag or the url) it will still update.
Now I have a feeling that you're not going to be able to view the screen print I uploaded very well, so I'm going to tell you what it says for the alt tag - born this way tattoo. Now why did I use this? When I first uploaded the image a lot of people were searching for images of her born this way tattoo and Google was directing some of the traffic to me because I talked about it although I didn't have an image I could use initially (lots of illegal ones doing the rounds mind you, but that's a whole new blog post!) - because most people were circulating an identical image that actually wasn't a very good one I wanted to dominate the traffic with this one. This is a valuable lesson - using your own stats and add keywords from them (if applicable) onto your lens OR make another lens on that topic which you can link to from your existing lens (if that's more appropriate).
It really is amazing how much traffic images can bring to your lenses so it's well worth checking out if you've optimized (but not over-optimized!) your images when you're updating your lenses. Remember also that sometimes you'll need to change your alt-tags depending on changes in what people are searching for at that time.