Resizing in Photoshop? Options

[GlamorousSky]

Is it possible to resize, from say, 300 to 3000 without the image being ruined?

I am trying to make a poster and it is required to be in A3 size, which is about 3000+ px, however, the pictures that I have used are only 300px.

Thanks in advance. :]

I'm using Photo Shop CS3 Extended, by the way.

[Gigi]

The largest you can possibly enlarge your picture by without losing an excessive amount of quality is 20%, and even then it's frowned upon. Anything greater than 10%, and you will start seeing bad quality.

You also have to take into account the resolution of the image. If it's colour, it should be at 300 DPI, and if it's grayscale, it should be 266 DPI. If it's line art or graphic art, it should be at 600-1000 DPI. I'm assuming that your 300 px picture is at 72 dpi, the res of most web images, so your chances of enlarging the image to 3000+ px is impossible, without grossly distorting your image.

Could I have a look at the image? It's possible to save it if you vector the shapes or something, or enlargen it and apply a filter or some sorts.