When it comes to images, the terms hi-res and lo-res get thrown around a lot. Unless you’re a designer or photographer, you may not know exactly what those terms mean — even if you think you do.
What’s the difference between hi-res and lo-res?
Simply, hi-res images are suitable for printing and lo-res images are suitable for the web. Hi-res images can be used on websites but will slow loading time for the site. Lo-res images can be printed, but only at very small sizes and without the quality you would need or want for printed images.
How do I know an image is hi-res or lo-res?
Image resolution is determined by the number of pixels per square inch. The higher the number of pixels, the higher an image’s resolution. The standard for printing images of quality is 300 ppi; more pixels make the image larger and therefore printable at larger sizes. For digital images, 72 ppi is standard.
How do I make a lo-res image into a hi-res image?
Trick question! It cannot be done. If you start with an image that is 300 ppi, you can lessen the resolution. Doing so removes pixels from the image and each of those pixels contains information that, once lost, cannot be regained.
On the flip side, if you start with an image that is 72 ppi trying to increase its resolution does not add information to the image. All it does is stretch the pixels already there. This is why, if you try to increase an image’s resolution, it gets blurry. It is always better to start with a hi-res image and lower the resolution.
Is it possible to have a hi-res image that is 72 ppi?
Another trick question, but the answer is yes! Almost all digital cameras and camera phones take images at 72 ppi, but with large enough dimensions that those images can still be used to create high-quality prints. But just because it works in this instance, increasing image size still won’t make a lo-res image into a hi-res image. All it will do is stretch the existing pixels to fill the extra space.
These are the basic differences between hi-res and lo-res images. The most important thing to keep in mind is that if you want to print an image, it needs to have at least 300 ppi. The higher the pixels per inch, the larger you’ll be able to print the image.