Answer:
You can use the:
- HTML interface (you do not have to download anything)
Go onto your account, click on your profile, click on "Photos" (a button up the top) and either choose an existing album or create a new one. The new album will brig up the upload interface, for the existing album you have to click on "Add Photos". If your browser supports Java it will automatically load the Java interface. You can switch to the HTML interface by choosing "Try the Simple Uploader" from the bottom of the dialog.
- Java interface (you need an up to date Java engine) - it works the same as the HTML upload and is the default option. The Java interface automatically resizes the images before uploading them, that is why the upload works faster as in the case of the basic HTML interface. The Java interface allows you to upload more than 5 photos in one single step.
- Third party applications (you have to download and install them) - like AZImage can simplify the process and provide better image quality and upload speeds. See related links for more details.