Pretty yellowed and dingy, huh? No worries! First, open up your photo in Photoshop.
Now hit Ctrl+L to open the Levels Tool. Click on the eyedropper tool on the far right that is white.
Make sure the Preview box is checked. Now click on an area of your photo that SHOULD be pure white. This may take a few clicks on different white spot to find the one that best corrects your image.
Play around, nothing is permanent. If you get completely off track just hit cancel and try again.
Sometimes the tint is corrected, but this process slightly washes out your photo. No worries. In the Levels toolbox click and drag on the black arrow and slide it towards the center until you have achieved a look you like.
There! You're done! Let's look at the fixed photo...
This trick is especially great for photos of little ones at bath time. Bathrooms often have yucky yellow lighting and limited windows. This tool makes your bath time photos bright and fresh! This is also great for correcting the tint of vintage photos with an odd cast or that weirdly pink glow some of my baby photos had.
Now go forth and color correct! Enjoy!