I've lost count of the number of times clients have sent me images they have taken from the web.
There is no point in sending to a graphic designer images that have come from the web . Most images downloaded from the web are not suitable for use on a printing press. If a printing machine had eyes, this is how it would see images taken from the web.
Printing machines require images with a high resolution of at least 300 dots per inch. Each dot represents a physical part of the image, the lesser the number of dots, the more coarse/broken the image as shown below.
The way to determine whether a picture is suitable for your print job is to look for its pixel size.
Find the image file in your Finder, right click the image and select Get Info. A pop-up window will open with the dimensions of your image displaying in the More Info section. The dimensions show the pixel height and width of your photo.
On a PC, right click on the image file, look at Properties, and then view the Summary tab.
Smart Phone Users
You can view the EXIF data easily from your phone, mobile device or computer. All you have to do is navigate to any image captured with your smartphone camera and open it to look at its EXIF data.
How to visually determine whether the images you send to a printing company is suitable.
View the image on your computer/smartphone and zoom in 300%. If the image looks sharp and crisp, without any pixelation or blurred edges, it is most likely suitable for sending to a printing press.
Here, you can calculate the size in pixels your picture needs to be for a printer: