That will change the dimensions of the image, perhaps you need the width to be the same as the width of a webpage you are adding the image to, for example. Adjust either the Width number or the Height number – the other will automatically adjust proportionally.Choose whether you want to resize according to pixels, percent, inches, cm, mm or points.

This means you can only change one dimension, length or width, but it means everything will be adjusted equally. Now, assuming want your image to look the same after – rather than stretched or squat, you need to make sure that Scale proportionally is selected.Choose Adjust Size (you can also open this menu by clicking on the square with arrows icon in the menu bar).Double click on the image – this should open the image in Preview, if it doesn’t, close it and right click to choose Open With and select Preview.Locate the image (either using the Finder, or on your Desktop).You can figure out what the options do by playing with them. It doesn’t matter if you’re not sure what the options do - the image will update in the background as you adjust these sliders, so you can see a preview of your color adjustments in real time. It’s useful for everything from fixing the color levels of an image to applying that old-timey sepia filter Instagram made trendy. The pane includes an overall color level graph you can modify as well as sliders for adjusting exposure, contrast, highlights, shadows, saturation, temperature, tint, sepia, and sharpness. Use the options on the pane that appears to adjust various color settings. The built-in Preview application also has a tool for adjusting the color levels or gamma of an image.

RELATED: Use Your Mac’s QuickTime App to Edit Video and Audio Files You can then click somewhere in the image to add text, draw a line, highlight an area, create a shape, or insert an arrow - whichever tool you’ve selected. Select a tool and it will replace the default “rectangular selection” tool. You can also click the Tools menu, point to Annotate, and select one of these tools in the menu. Preview includes various image mark-up tools - the same ones that work in PDFs - which you can access by clicking the Show Markup Toolbar button near the top-right corner of the window.

How to crop a photo in macbook