program to print posters without pixels

[alucard2050]

i have a program that lets me print posters. i print it out onto 8.5x11 sheets and i can select how many sheets to use. i normally use 4 sheets. but, here is my problem. with the picture being enlarged i guess thats what causes it to pixelate alot..is there a program that someone can recommend to do posters that will enlarge the picture without makeing it blocky? i print them on just one 8.5x11 sheet and its perfect but any larger and i get the pixels.....thanks.........

[vitualis]

Tips:
Firstly, use a higher resolution picture!

Secondly, if you can't do that, then use a program like Paint Shop Pro to resize your image / increase your image resolution. It will do it better than your printer --> minimising pixellation.

Thirdly, make sure you have enough RAM to print huge high resolution pictures.

Regards.