Step 1: Starting image
If you don't want to use dozens of yarns at once , it's worth tweaking your image to reduce the number of colours in it. I started with the Robot image from this topic, and used Photoshop to add extra space around it, and cut down the number of shades in the image.
Uploading the image to Pics To Knits was actually quicker and easier than uploading an image here.
Step 2: Cropping and selecting complexity
You can select the number of colours you want to play with from the thumbnails at the bottom of the screen - the more colours you choose, the more accurate the final knitted image, but the more skeins of yarn you have to juggle as you knit.
I went with the "four colours" option.
Step 3: Tweaking colours - make it fit your stash.
To save time and stress, I made the two odd shades of beige ("A" and "B" on the screen shot) into black, by clicking on the labelled colour, then clicking on the colour I wanted at the right hand side.
I also changed the background from orange to blue, because I realised I don't have any orange in my stash.
The site realises when you have chosen more than one part of the pattern to be the same colour, and reduces the number of blocks on the key.
I then hit the "make pattern" button to create a PDF of the pattern.
If you are going to print out the PDF file, be careful - the version created for me had 14 pages, but every other page only had a title on it, and the last page was completely blank (if you're from PtK, that needs fixing, because it's annoying). I didn't print the pattern, though, I just sent it to my iPod via email, then worked from the screen.
Step 4: Knit it.
Be aware that the pattern is written in English knitting code (although the translation is simple) - when it tells you to knit or perl so many of a particular letter, then refer to the key to see which colour they mean.
For this cushion, the pattern only makes the front, 40cm square. For the back, I knitted two rectangles that over-lapped when I made the cover up, so that I could use the envelope-style gap to stuff the cushion into the cover. If you are going to stuff the cushion, you could just make a simple square and sew up most of the way round before stuffing and finishing off.
If you follow the pattern exactly, you get four separate squares that you need to sew together. To cut down on seams, I knitted each side continuously, without casting off and on between the top and bottom squares. This gave me two tall rectangles to sew together.
Next time I do this, I plan on following the pattern continuously, all the way across from side-to-side, simply by reading the top line of the top-left square, then the top line of the top-right square, then the second line of the top-left etc, finishing off with the last line of the bottom-left, then the bottom line of the bottom-right. I will probably have to tape the pages together into one large sheet, but it will be worth it.
Step 5: Making up and finishing off.
Despite Kiteman's moaning, I decided not to add the red details afterwards - it will stand too proud of the surface, and if I stitch it tight enough to be smooth, it might pull the rest of the cover in funny directions.
Thanks for reading.
Step 6: And finally...
Because the pattern is digital, you could even send it to people around the world, then all post your squares to one person to sew together.
You could also use these patterns to make panels for jumpers - if you want to avoid having to stitch across the pattern, then upload a file with the image in just one corner (see the image on this step).
Downside? Like I said, the patterns can waste a lot of paper if you just hit "print", but apart from that, Pics to Knits seems to be an awesome resource, especially since it's free, and you can use the images for anything you want. They're new to the Making scene, but I think they'll go a long way.