An image hosting service allows individuals to upload images to an Internet website. The image host will then store the image onto its server, and show the individual different types of code to allow others to view that image.
Hosting services have the potential ability to identify when and where their images are being used. When an image file is accessed, the image host is capable of logging the date and the general numeric internet address of the request.
In the case of spam, the messages often include unique image URLs that are specific to that message only. The unique URL is used as a tracking ID, so that the image host can identify exactly what message intended for what specific recipient has been viewed, in addition to the date and host accessing the image. This is why many email reading systems do not show images by default, to protect the reader from having their reading of spam being tracked by the email senders.
How it works
Typically image hosting websites provide an upload interface; a form in which you specify the location of an image file on your local computer file system (using a browse button). After pressing a “Submit” button the file is uploaded to the image host’s server. Some image hosts allow you to specify multiple files at once, in this form, or the ability to upload one ZIP file containing multiple images. Additionally, some hosts allow FTP access, where single or multiple files can be uploaded in one session using FTP software or an FTP-capable browser.
After this process, your image is hosted on their server. Typically this means it is available on the web (to the public). You may also be allowed to make inline links to the hosted image, to embed it on other websites e.g.
- Linking with HTML code
- Linking with BBcode
- A clickable thumbnail that is linked to the full image
Usually, the image host will put restrictions on the maximum image size allowed, or the maximum space or bandwidth allowed per user. Due to bandwidth costs, free services usually offer relatively modest size limits per image when compared to paid services, but allow users hotlinking their images.
Image hosts also allow tools such as the ability to create photoblogs/galleries with your images, or add them to a slide show for easier viewing. Some offer more advanced tools such as the ability for an individual to add notes to an image they uploaded,side loaders, or browser sidebars. Other hosts have introduced novel features such as the ability to automatically resize images down to a user-selected size. A Flickr tool allows you to upload photos using a camera phone with email capability.
Many image hosts are free, some don’t even require registration. Of the free image hosts, the vast majority are supported by advertisements, mostly on their top pages, thumbnail pages, or “not found” pages. Showing advertisements to users has enabled image size and bandwidth limits to increase.
Some free hosts have optional paid image hosting functions, while other hosts offer only paid services. Features and storage available are generally better for paid services, while cost is still much less than the cost of purchasing web hosting to operate a website. Paid services often allow users to have password protected photo albums, customizable skins, and customized subdomains. There are many other paid services available that offer different packages of options, features, and costs.