Compress your images. Readers tend to get annoyed when they’re waiting for a 2MB image to load when it should be only 20k instead. Graphics software like Photoshop can compress images so they take up less space in your hard drive, which in turn take less time to load into your visitors’ browsers. The best recommendation is to get a graphics software and shrink those file sizes.
Image editing software, such as Photoshop, can adjust many variables in your image. Some are relative variables, and some absolute.
If you scale the image down, Photoshop will decrease the number of pixels in the image by resampling them (averaging the values of neighboring pixels to make new pixels), if try to increase the number of pixels in your image Photoshop will interpolate new pixels (inventing new pixels based on surrounding ones) giving you a bigger, but fuzzier, image.
The way to control this is with the “Resample Image” option in Photoshop’s Image Size dialogue box. If “Resample Image” is on, and you change a document Size measurement (Width, Height or Resolution), it will adjust the number of pixels accordingly, either scaling down the image, or resampling it up (decreasing image quality). If “Resample Image” is turned off, you cannot change the Pixel dimension, and changing the Resolution will affect only the Document Size and vice-versa.
Tip 1: You can see the dimensions of your image in pixels by hovering your mouse over the file name in your computer’s window browser. To calculate the size in inches that an image will be when printed divide the number of pixels by the print resolution. To calculate what size your image will be on screen divide the number of pixels by 72.
Tip 2: When cropping and resizing an image, to work out the correct size multiply the number of inches by 72. This will give you the dimensions in pixels which is the numerical value used in html code. For example, if you want a 6×4 inch photo, the pixel width and height will be 432 x 288.
Tip 3: Whenever resizing your images for use in websites, never overwrite the original image, just in case you need it later for print. Instead, give it a new name. Images can always be downsized but never upsized – they become pixelated and of poor quality.
Tip 4: If you want to show a larger version of an image, you can always include a link to the original image. If the image belongs to you and you do not want someone else claiming it as their own, add a watermark of your name on it.