Thats format in which image data will be stored. Difference is because some image formats allows you to save editeble layers along with file (PSD) and some don't (JPEG, GIF, PNG).
psp is used by photoshop.
Photoshop has ties with other Adobe software for media editing, animation, and authoring. The .PSD (Photoshop Document), Photoshop's native format, stores an image with support for most imaging options available in Photoshop. These include layers with masks, color spaces, ICC profiles, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is in contrast to many other file formats (e.g. .EPS or .GIF) that restrict content to provide streamlined, predictable functionality.
almost any format:.jpg , .gif , .png are most common but you can open almost any other format
Just save it in format zou want, you can do that from File - Save , Save as, Save for Web and Devices
Do you mean how to resize image? First open image from File > Open in Photoshop then go to Image > Image Size. If you want to edit image you can do that regardless of source of that image. Image can be scanned, captured by digital camera, created in Photoshop or any other software available on market. If Photoshop supports that file format (JPEG, TIFF, PSD, PNG and so on) then you can edit it.
Adobe illustrator (AI) is a vector file format to save vector illustrations. It is the default format for Adobe illustrator. Photoshop cannot save the images in to AI format but it can be opened in Photoshop.
In Photoshop - PSD file format.
Yes, Adobe Photoshop does support GIF images. GIF (Graphics Interchange Format) is a popular image format that supports both static images and animations. In Photoshop, you can open and edit GIF files just like any other image format. You can also create and edit GIF animations using Photoshop's animation tools. Thanks!
Any image editing software such as: Photoshop, paint, gimp, etc
The main reason for exporting is to take the file for editing into another application. For example, if you are working on a file in Photoshop, it is a PSD file. The PSD is Photoshop's special format that contains layer information, applied filters, and other info specific to Photoshop. Now if you wanted to take the image to a web-ready format, you would have to export it. In this case to a GIF, JPEG, or other web standard format.
You cannot directly. You have to open it in 3D Studio Max, then save it to a format that is supported by Photoshop (typically you will render it to a jpeg for example), then you can open it with photoshop or ther image editing software.
Its not Photoshop PNG but rather PNG-8 file format. Use it to save files with limited color palette (max 256) to have file with smaller size for Web which can contain and transparent areas in image.