[Wikitech-l] question about standardized thumbnail sizes

Hi Sumana! We are working on some form of standardized thumbnail sizes, but it is not exactly the same issue that is discussed in the RfC <https://www.mediawiki.org/wiki/Requests_for_comment/Standardized_thumbnails_sizes> . The problem we have ran into is that MediaViewer fits the image size to the browser window size (which means a huge variety of image sizes even when the browser window is fully enlarged, and practically infinite otherwise), but thumbnail rendering is very slow and waiting for it would result in a crappy user experience. We started using a list of standardized thumbnail sizes, so that MediaViewer always requests one of these sizes from the browser and rescales them with CSS, but even so the delay remains problematic for the first user who requests the image with a given bucket. To address that, we are working with ops towards automatically rendering the thumbnails in those sizes as soon as the image is uploaded. Another possibility related to standardized thumbnail sizes that we are exploring is to speed up the thumbnail generation for large images by having a list of sizes for which the thumbnail is pregenerated and always present, and resize one of those thumbnails instead of the original to generate the size requested by the user. The goal of this would be to avoid overloading the scalers when several large images need to be thumbnailed at the same time (GWToolset caused outages this way on a few occasions). I can create an RfC about one or both of the above issues if there is interest in wider discussion. I don't know whether the current thumbnail size standardization RfC should be replaced with those, though; its goals are not stated, but seem to be mainly operations concerns (how to make sure thumbnails don't take up too much storage space). Maybe ops wants to take it over, or provide clearer goals in that regard for the multimedia team to work towards.