How to resize an image without losing quality in Adobe Illustrator
1- Open Ai.
2- Open your image.
3- When you resize some images you will find that they become pixelated. You can see this below.
4- A way to stop this from happening you can do the following. - Select the image, in the top toolbar select image trace drop down box. Select high fidelity photo.
5- Next select Expand in the top toolbar.
6- This will have adjusted your image. Hold the shift down and drag your image bigger.
7- As you ca now see there are no pixelated edges.
It is good to note that this technique will not work on every image but it is good to try to improve the quality of your images. Image is from Design Bundles and the image set is called customizable outline icons.