Using Images

An image is said to be worth a thousand words. In e-commerce, this is almost always true. The downside of e-commerce is that customers cannot try on clothes or handle items they might like to buy. Providing customers with great images helps overcome that hurdle.

Topics

Understanding Images Supplied by Amazon Associates Web Service

Amazon catalogs millions of product images. These images reside on a series of servers dedicated to serving images, as you can see from the URL of one image:

http://images.amazon.com/images/P/B000BNM5OA.01.SWCH._SCMZZZZZZZ_.jpg

All image URLs have a common structure:

Endpoint for all images, which is http://images.amazon.com/images/P/
An alphanumeric token that identifies the image, for example, B000BNM5OA.01.SWCH. The 01 is a country code. The country codes are as follows:
Country codes are valuable because the language in the figures varies by locale.
A suffix that specifies the size of the image returned. Possible suffix values are:

	Note
	The Small and Thumbnail sizes are the same.The filename of the image always contains "THUMB." Initially, this image was called "SmallImage" in the response elements. Amazon Associates Web Service added the "ThumbnailImage" response element because it more closely resembles the filename of the image.

Looking at the suffixes, you can see that the "Z"'s are meaningless placeholders used to create a twelve-digit suffix. Also, you can see that the file format for images is jpeg.

The following figure shows the relative sizes of Large, Medium, and Small images.

	Note
	Thumbnail and Small images are the same size.

Notice that all of the images are the same, just in different sizes. This corresponds to the image ID being the same for all of the above images, just the suffixes, which indicate size, are different. Each image is about half the size of the next larger size.

The smallest sizes are Swatch and Tiny. Swatch size, is available only with items that have variations. A variation is a group of items that are closely related, such as the same shirt that varies only by size or color. Typically, you use the swatch size to display all of the variations of an item.

Hard coding image URLs into applications is not recommended because images come and go. Using the Images or VariationImages response groups to return images guarantees up-to-date image URLs. Once you retrieve the image URLs, you can manipulate just the suffixes of the the image name to display the different sizes of the image. This technique saves you from having to send separate requests for each image size.

Image Details

The following XML shows how images are returned by Amazon Associates Web Service.

<Item>
  <ASIN>B000BNKS80</ASIN> 
  <SmallImage>
    <URL>http://images.amazon.com/images/P/B000BNKS80.01.
    _SCTHUMBZZZ_.jpg</URL> 
    <Height Units="pixels">75</Height> 
    <Width Units="pixels">50</Width> 
  </SmallImage>
  ...

Notice that each image is associated with an item identifier, which, in the above example, is an ASIN. The image details include the:

Image's size, which is captured in the element. In this example, the size is SmallImage.
Other sizes include <LargeImage>, <MediumImage>, <SwatchImage>, <ThumbnailImage>, and <TinyImage>.
URL of the image on Amazon's image server
Image's height and width measurements in pixels to aid in displaying the images. The standard resolution is 24 bit color and 96 pixels per inch.

For each image size, this format of information is repeated.

<ThumbnailImage> 
<URL>http://ec1.images-amazon.com/images/P/0440415632.01._SCTHUMBZZZ_.jpg</URL> 
  <Height Units="pixels">75</Height> 
  <Width Units="pixels">51</Width> 
</ThumbnailImage> 

<TinyImage> 
<URL>http://ec1.images-amazon.com/images/P/0440415632.01._SCTZZZZZZZ_.jpg</URL> 
  <Height Units="pixels">110</Height> 
  <Width Units="pixels">75</Width> 
</TinyImage> 

<MediumImage>
<URL>http://ec1.images-amazon.com/images/P/0596100574.01._SCMZZZZZZZ_V45139426_.jpg</URL> 
  <Height Units="pixels">160</Height> 
  <Width Units="pixels">122</Width> 
</MediumImage>

<LargeImage>  <URL>http://ec1.images-amazon.com/images/P/0596100574.01._SCLZZZZZZZ_V45139426_.jpg</URL> 
  <Height Units="pixels">500</Height> 
  <Width Units="pixels">381</Width> 
</LargeImage>

All small size images are not the same size, nor are all medium nor all large size images the same. This, in part, is due to the different shapes of items. Some, for example, are taller than they are wide, others are the opposite. The number of pixels can vary by 100 (or, roughly an inch) per dimension across all similarly sized images. Regardless, the relative size difference between a SmallImage and MediumImage is roughly the same across all images.

Given these variations, you can see that it is important not to hard code image sizes into your application.