Product Images and Videos in the RP Photonics Buyer's Guide

Until recently, advertisers could display only a single product image per registered product category. Now, we have improved this substantially:

• We now support not only images, but also videos. In that case, a preview image supplied by the advertiser is displayed together with a superimposed Play button. When clicked, the video is played in an expanded display area.
• Note that previously we already allowed displays of some videos, but not one for each product category.
• We now allow up to five media items (images or videos) per category. This can be very useful, e.g. for showing multiple products of a category, or different details of one product.
• To save screen space, only one item is shown at a time. Below it, up to five thumbnail images indicate the additional available items and allow users to switch between them with a click. As an example, see one of our own displays:

Some advertisers immediately started providing additional media items, significantly improving the presentation of their products.

The media items are now also displayed at a somewhat larger size: 300 px width instead of 250 px. Since computer screens have become substantially larger and sharper in recent years, this makes sense for many users.

Image resolution is a somewhat trickier issue than one might expect. In the following, I provide some useful background information and practical hints for those who are interested. But we do not require advertisers to study such details; they are welcome to upload large images, and we rescale them as appropriate.

The main goals are to achieve high image quality while avoiding unnecessarily large image files, which would increase loading times — particularly on mobile devices with limited Internet bandwidth.

As mentioned above, product media items are displayed with a width of 300 px. Interestingly, that does not mean that image files with exactly 300 px width are ideal. Modern operating systems commonly apply screen scaling factors such as 150% on Windows or 200% on many Macs. Some background information:

• Modern computer screens have far higher pixel densities (dpi values) than older screens. If images were displayed using the same number of pixels as before, they would appear physically much smaller on high-resolution displays. Therefore, operating systems such as Windows and macOS scale display elements (text and images) to 150%, 200%, or similar values. Users can configure that scaling factor in the system settings.
• Suppose an image file has a width of 300 px and is displayed at a nominal width of 300 px. With 150% screen scaling, however, the actual display width becomes 450 px. The operating system must then upscale the image, causing some loss of quality. Ideally, the image file would therefore already have a width of 450 px. With 200% scaling, even 600 px would be optimal, although 450 px is already substantially better than only 300 px.
• Technically, a web server could provide different image versions depending on the screen scaling factor, allowing the browser to select the optimal version. However, for images of this relatively modest size, the benefit would not justify the additional technical complexity. Such methods are more useful for substantially larger images.

Our current approach is therefore to scale advertiser-provided image files down to 450 px width, except when the supplied resolution is already 600 px or less. Before resizing, we often remove unnecessary margins. JPG images are then saved with a quality setting chosen for a reasonable compromise between image quality and file size.

Some advertisers send PNG images, presumably to avoid the lossy compression of the JPG format. In practice, however, this usually results in far larger files without any significant improvement in visual quality. We therefore often convert such files to JPG.

In addition, our web server also provides each image in WEBP format. This Google-developed format offers significantly better compression at the same quality level and is therefore preferred whenever supported. All modern browsers can display WEBP images, while older browsers still receive JPG (and occasionally PNG) versions.

For each displayed supplier, there is a form for reporting changes. From the supplier profile page, you get there by clicking on the red button “Edit profile data” near the top right corner.

This form offers various buttons for image upload. In case of product images, first go to the section “Offered products”, find the relevant product category and click on the corresponding button “Edit product description and image”. There, you find the button “Upload images and videos”, which opens a convenient upload feature:

Here, you can upload all relevant media items for one product category. Proper explanations make clear what you need. Click on the appropriate “Select file” buttons to chose files in your file system, and finally upload all by clicking on “Upload selected files”. This does not directly change any displays on the website; instead, it sends those files to use for processing. If anything special should be observed, enter a suitable comment.