• "Eyedropper" and "Color Sampler" are two types of color selection tools.
• The "Eyedropper Tool"allows you to pick a color from an image that exists already.
• The "Color Sampler Tool" allows you to view color values in defined spots of your image.
• Each an every color selected by these tools are displayed in "Info Palette". Press "F8" to display info palette.
• Just select the "Eyedropper Tool" from toolbar, click on the required color on the image.
• Color picker will display the colour chosen by the "Eyedropper tool" automatically.
• You can pick up a color, not only from the image opened in the Photoshop's workspace but also from other applications.
• The "Color Sampler Tool" is same as the eye dropper tool.
• User can mark upto four sample colors on your image, and the details are displayed in the "Info Palette".
• To delete a sample, "Right click" on the sample in the image and select "Delete".

Video Tutorial: