How do I up the resolution of a Jpg?

[Angel Tarragon]

I have an image I wnat to use for a private project on Lulu, but I get a message that it doesn't have a high enough resolution to be good for anything but a download. So how can I up its resolution?

 

[Thanee]

You can do that with pretty much any picture editing software (i.e. The Gimp or even the viewer IrfanView, both are free).

But it will likely look pretty bad, if you increase the resolution, since the image is stretched to the bigger size, extrapolating from the original picture.

Bye
Thanee

 

[GlassJaw]

If it's an existing image, you are pretty much out of luck. As Thanee said, you can increase the resolution but that will most likely make it look worse.

If you want high-quality and high-res, you need to set that when you create the image (or scan it).

 

[ssampier]

That's a by-product of a raster image. A vector image should scale to any size, really.

 

[GlassJaw]

That's a by-product of a raster image. A vector image should scale to any size, really.

Why would you assume it's a vector image he's working with?

 

[Angel Tarragon]

What the heck is the difference between raster and vector and how can I tell which type I have?

 

[Glyfair]

What the heck is the difference between raster and vector and how can I tell which type I have?

It's jpg so it's raster. Vector images can be viewed as close as you want without the "pixelization" you get with things like bmp & jpg. Essentially vector images are stored as instructions for drawing the image.

Campaign Cartographer 2 stores it's images in vector format, for example. In theory you could draw a map and zoom from the world level to the village level (in practice that takes a lot of computer power to do and isn't very practical).

 

[Thanee]

What the heck is the difference between raster and vector and how can I tell which type I have?

Raster = A big matrix of colored points
Vector = Lots of lines with direction and length

Basically.

Vectors, naturally, scale with size, while the raster image is fixed and can only be extrapolated.

All typical images are raster images, though.
Vector images are only used in special applications (technical drawings and such).

Bye
Thanee

 

[Pyrex]

...So how can I up its resolution?

Generally speaking, you can't.

However, the problem is that some apps look at the resolution of the image (in pixels-per-inch) instead of the size of the image in pixels.

Say you have an image that's 300 pixels tall by 300 pixels wide.

If you want to print it at 1"x1" you're gold, becaus that gives you a resolution of 300 pixels-per-inch.

Try to print the same image at 6"x6", and it'll look bad, because then you've only got 50 pixels-per-inch.

How large (in pixels) is your source jpg? How big do you want the final print to be?

All typical images are raster images, though.
Vector images are only used in special applications (technical drawings and such).

Several greeting-card type programs store their clip-art in vector format as well, as it allows cartoony images that take up virtually no storage space.