More on the performance / browser choice debate graphed below:  
 
Unrelated source, but the economist had this to say:  
 
"  
For instance, people who fill out online job applications using browsers that did not come with the computer (such as Microsoft’s Internet Explorer on a Windows PC) but had to be deliberately installed (like Firefox or Google’s Chrome) perform better and change jobs less often.  
 
It could just be coincidence, but some analysts think that people who bother to install a new browser may be the sort who take the time to reach informed decisions. Such people should be better employees. Evolv, a company that monitors recruitment and workplace data, pored over nearly 3m data points from more than 30,000 employees to find this nugget.  
"  
 
http://www.economist.com/news/business/21575820-how-software-helps-firms-hire-workers-more-efficiently-robot-recruiters

Are Apple users cleverer than PC users?

Well, unless it's related to sudoku completion times, I don't know. The differences are startling, up to 50%!:
 
You choice of browser seems relevant:
   
 
As does your choice of computer:
 

 
To show there's really nothing up my sleeves, and those are the bare facts, there's a Spreadsheet Here of our logs of completion times, grouped by operating system, and browser. I've even graphed the distribution for you.
 
I'm sure there must be heaps of mitigating factors - maybe iPad users are slowed down by fat fingers. Maybe PC users are playing it at work and have to stop playing when the boss walks past. Just maybe there's a correlation with intelligence and IT choices.

This Apple is the Droid you're looking for.

When you browse the web, your computer tells the website a little about you - kind of like a valet travelling on ahead to tell your host what you like for breakfast, and what size bed you need (sort of). All browsers do this. It looks something like this:  
 
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-us) AppleWebKit/533.16 (KHTML, like Gecko) Version/5.0/Safari/533.16  
 
You might (quite reasonably) assume the above 'User-Agent' is an Apple Mac - there are no clues that it's not.  
 
It turns out though, that the default browser on Android is telling the sites you visit that your android tablet or phone is an Apple Macintosh. Now, I could understand an Android device identifying itself as 'like iPhone' or some such so that Android users get the mouseless versions of sites intended for iphone users, but it doesn't say iPhone, it says Macintosh - the big ones with keyboards. And neither does it say 'like'. It says it's an Apple Mac running Safari.  
 
Why?  
 
Did Google developers copy and paste a bit of code from Safari and forget to change that bit?  
 
Is it so that facebook doesn't work properly and you have to use Google+?  
 
Is it an in joke at Google?  
 
(N.B. In case you stumbled on this page looking for a work around, Android devices say the navigator.platform is Linux armv7l - which is a little vague, but different to an Apple Mac)

Ayanna, just for you:  
 
http://www.picturesudoku.com/PlainSudoku.htm

Sorry it's been a while

Roxanna, these puzzles are made in Javascript.  
 
BJ, There are loads on Amazon.  
 
Joyous - done. There's now a picture of a white tiger instead.  

Puzzling indeed

What browser / operating system are you using?

Hi Kira,  
 
We allow other sites to sue our code to create picture sudokus on their own site. The circle / octagon one which you are referring to is one of those and we have no control over the images they use.  
 
Best Wishes,  
Simon

Mike, weren't you called Susan Yesterday?

for your site

'how to solve sudoku', you've probably figured it out by now anyway, but please go to 'free sudoku for your site' link at the top of the page and follow the instructions there.

Shape sudoku

Kira - the shape sudoku on this site has only straight lines.

Grid size

I did look at being able to change the grid size at one stage but a smaller grid is too easy, and in a larger grid, the pictures get too small. So the grid size is 'hard wired', and changing it would add a surprising amount of complexity.  
 
For a fee, I could make you a custom version, but it would be quite a lot of work, and I couldn't do it in the time frame.  
 
Best Wishes,  
Simon

Hi Jo,  
 
1) Upload some pictures to a photo sharing site, like photobucket.com  
2) Once you've uploaded them all - go to this page and follow the onscreen instructions:  
 
http://www.picturesudoku.com/custom.htm

Difficulty level

Do you want harder puzzles, or easier puzzles? (i.e. how would you rate the average puzzle here in your scale?)  
 
The trouble is, Sudoku's here are randomly generated; some are hard, some are easy.  
 
From a given starting point, we can make it easier, but making it harder is ... erm... harder.

I'm timing you...

I've just started timing how long it takes to complete a puzzle, together with browser infomation, etc.  
 
This might make for some interesting stats:  
 
Are users of a particular setup cleverer than others?  
Which site has the cleverest users?  
 
etc

Update

* Adding the stylesheet amendment seems to have made the IE bug go away. By that, I don't mean it's died, I mean, it goes on to the next site you visit instead of this one.  
 
* The program makes a sudoku grid around 99 times out of a hundred. It can time out if you get an unlucky random combination, and you have a slow machine.

Big photo selection

Pictures are now twice as large in the selection grid, by placing it in a layer above the main puzzle grid. (If that's Greek to you, don't worry about it)  
 
Thanks to Quirksmode for a few genius lines of script that proved very useful for this.

Interface?

Puzzle Lover,
It's the piece you click that gets placed. Is that not obvious?  
 
Maybe it's not working for you. What do you see when you mouse over an empty square?

Internet Explorer Trailing

It turns out that we have found a bug in internet explorer. I can't find anything about it online, so it seems it's a new one.  
 
If you scroll the page, once the picture sudoku has loaded, you'll see it leaves a trail, rendering the puzzle unviewable, and unusable. Fair enough, you may say, that's jsut Picture Sudoku's dodgy programming you may say. so you type in another URL in the address bar. But behold, the next page you view will then have the same issue, as will any page, on any site that you view afterward. What witchcraft is this?

Flawed, but functional

Another two day project that lasted two weeks, but finaly, here it is.  
 
* The program doesn't always create a puzzle at the first attempt.  
* Grids are not symmetrical. When they were, there were a few too many 'clues' given. The starting grid is created by starting with grid of very few numbers, and then trying to solve it using 'easy' methods. If it can't solve it, it adds in another clue.  
* It's a bit easy for some - I'll make it harder in due course. If you add it to your site, you will automatically get the increased difficulty levels when they become available.  
 
Enjoy!  

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