The best way to resize an image and/or resolution is to use Adobe Photoshop. Simply because you can easily manipulate image size, width, height and resolution. This is one of the useful technique in Photoshop and you will use it all throughout your graphic designing.
Follow the step by step procedure:
Step 2: Click on Image, Image size, you can change the pixel dimensions, image dimensions and resolution. You can interchange the unit from pixel to inches and to other unit of measurement. Tick the Constrain Proportions to apply changes automatically once you change either the width, height or resolution.
Step 3: Save your work. Go to File, Save as, then write the file name and choose the file format, then click Save. Most common file formats are .JPG, .BMP and .PNG, make sure that you save it in Adobe Photoshop format .PSD in order for you to edit anytime.
Tip and Tricks:
Press Alt + Ctrl + I for Image Size
Press Shft + Ctrl + S for Save As
Press Ctrl + N for New Canvas
Press Shft + Ctrl + L for Auto Tone
Press Alt + Shft + Ctrl + L for Auto Contrast
Press Shft + Ctrl + B for Auto Color
Tip and Tricks:
Press Alt + Ctrl + I for Image Size
Press Shft + Ctrl + S for Save As
Press Ctrl + N for New Canvas
Press Shft + Ctrl + L for Auto Tone
Press Alt + Shft + Ctrl + L for Auto Contrast
Press Shft + Ctrl + B for Auto Color
Travel Advisory: