Here is a Toronto based firm that produces quality product from your digital images. I recommend using them because they will not make a print if the size you specify does not meet quality criteria.

http://www.posterjack.ca/

We recently ordered a 30 inch mosaic that I created using approximately 286 images. I am inserting it on this page and you will have to scroll horizontal to view the entire selection. (depending on your screen resolution settings) To create this mosaic I used AndreaMosaic software that does this and then used Photoshop Elements to insert the text, got the digital file to 200 DPI, then emailed the image in JPG format to Posterjack. There are special considerations to keep in mind when getting mosaic prints made. In my case a 30 inch was not the correct size to ask for. See more information beneath this image.

The following information was provided courtesy of of Posterjack.

For the poster sizing, it all depends on the proportions of the digital image. In your case, there was not a fit between the dimensions of the image and that of the poster size you selected. In the future, if you have regular digital photos, this should be easy as we offer sizes in both 3:2 and 4:3 to accommodate the most common aspect ratios of digital cameras.

Once you have uploaded an image, if there is not an exact match in aspect ratio you can do one of three things.

1. Switch the poster size to one that has a matching proportion
2. Keep the same poster size, and leave the default layout on "fit to photo", which will not crop your image and print it slightly smaller than the size you selected
3. Keep the same poster size, and change the layout option to "fit to poster", which will crop some of your image in order to get it to print at the exact poster size you have chosen.

In your case - if you wanted an exact 20x30 poster, the best place to start would be to size the digital image to 3:2 proportions. Your current image is 2000x1650, which is not 3:2.