At Picturecraftwork.com you can convert images to a cross stitch chart delivered in PDF format. It is a simple three step online process. You upload and image file via a simple interface, manipulate the number of colours, and brightness and contrast until you have the desired result you are looking for. An advanced interface option is available in which you can change the hue and saturation levels too. Then when you are happy with the image click “Generate chart”. Patterns with less than 1000 stitches are generated free larger designs are 5 Euros paid for by paypal.
The site is bilingual offering English, Dutch, French, and German sections. If you want to convert the odd image to a cross stitch chart and only occasionally do so instead of paying for software to do it this would prove to be an economical option. However if you convert a good number of images I would suggest you invest in the software to do it.