Posters Rejected due to pixels?

I have a Pentax K100D 6 Megapixel Digital SLR camera.
When I upload prints to make a poster, I always get rejected for anything over an 8 x 10. I maximize the pixels before uploading them. Is there a way to increase pixels so I can make a poster? THANK YOU!!

What size resolution are you shooting at? Unfortunately, many companies don't distinguish between SLR pixels and point and shoot pixels, not understanding that a 6mp SLR will make better images than a 12mp point and shoot.

The simple solution is to simply "up-rez" your image file. Using software, like Adobe Photoshop Elements, simply open the file, resize/resample it to a higher resolution (example: if the image is 2000 x 3000 pixels (6mp), a resize to 3000 x 4500 pixels (13.5 megapixels) should solve your problem.

I don't know if you've got software that can resample and upsize, but if not, there are software packages out there to upsize (Photoshop, genuine fractals, Paint Shop Pro, etc.) Your included software that camera with the camera may have it too.

NO. You can't increase the pixels of your camera. You camera has a 6mp sensor there is no button that can change the psychical hardware inside.

You can turn a 6MP photograph into whatever resolution you want by uprezzing it. Here's how you'd do that in PhotoShop: http://www.outbackphoto.com/workflow/wf_...

Of course, the print WILL become softer, the more you blow it up. This process won't fool anyone for commercial work, but for private use at least the file will be accepted for printing and the result won't look pixelated.