Create/ open a image in the Photoshop to save them in a different file formats,
Step 1 : Choose "Save As" from the File menu.
Step 2 : Click on the "Format" drop down menu and select the file format you would like to use.
Step 3 : Navigate the file system to choose the location for your file to be saved.
Step 4 : Click the "Save" button.
Here are some of the most used file formats that Photoshop allows you to save the images.
.PSD : Photoshop Document format which stores an image with layers , masks, colour spaces, text, text effects etc. When you design a page in the Photoshop saving the image in .psd format makes you open the image later to do any modifications.
.BMP: Bit Map Image, called bitmap or DIB file format is an image file format used to store bitmap digital images, storing in this file format in Photoshop takes much size of the image, for example double the size of .jpg
.JPEG: Joint Photographic Experts Group, is the most common image format used by digital cameras and other photographic image capture devices. The photos taken from your digi cams can be imported into Photoshop directly to add some effects or sharpen the images to see the print quality in a better way.
.PNG: Portable Network Graphics is a bitmapped image format created to improve upon and replace GIF (Graphics Interchange Format) nowadays png file formats are most used in the internet.
TIFF: Tagged Image File Format is a file format for storing images, including photographs and line art. These file formats are most used in publishing media and designing page layouts.
Photoshop also has the option of saving the images for web.
From the file menu, select “Save for web” option to see how Photoshop optimises the size and quality of the image which would be best for your website.
If you could see from the screenshot above the original size of the image is 118kb and since you have selected “Save for web” option Photoshop has reduced the size of the image to 8kb which would the best quality which can be used for the website/internet.
If you still wanted to optimise the image, you can select the file format in the Save for web as “.GIF”. Now see how much difference in the size you get. But .GIF formats are advised to use only when the image you have created doesn’t have multi colours. If you use this file format to save, you have to loose most of the colours that were used during your design.