Flickr is facing a user revolt after a new auto-tagging system labelled images of black people with tags such as “ape” and “animal” as well as tagging pictures of concentration camps with “sport” or “jungle gym”.

The system, which was introduced in early May, uses what Flickr describes as “advanced image recognition technology” to automatically categorise photos into a number of broad groups.

For instance, a picture of a newspaper cartoon can be automatically given the tags “drawing”, “sketch”, “cartoon”, “text”, and “writing”, in addition to whatever else the uploader decides to add to the photo. Other tags the system can automatically append include “outdoors” and “blackandwhite” – referring to the picture’s setting and image type.

But the system appears to be misfiring frequently, and often in offensive ways. A portrait taken by Corey Deshon of a black man named William has been auto- tagged with “blackandwhite” and “monochrome” – but also with the words “animal” and “ape”.

The system itself doesn’t appear to be applying race as a factor, since at least one other photo, of a white woman, was also given the “animal” and “ape” tags.

Elsewhere, photos of Dachau concentration camp have been auto-tagged with the “jungle gym”, “sport” and “trellis” tags, while an instantly recognisable photo of the entrance to Auschwitz was given the “sport” tag.

A Flickr spokesperson said: “We are aware of issues with inaccurate auto-tags on Flickr and are working on a fix. While we are very proud of this advanced image-recognition technology, we’re the first to admit there will be mistakes and we are constantly working to improve the experience. If you delete an incorrect tag, our algorithm learns from that mistake and will perform better in the future. The tagging process is completely automated – no human will ever view your photos to tag them”.

The company is already reacting in a piecemeal manner to the mistags, removing the “sport” tag from many concentration camp photos, and apparently removing “ape” from the auto-tagging software’s lexicon entirely (neither of the photos which were tagged “ape” are tagged as such any more, though both still have the “animal” tag).

The auto-tags on the photo of William. Photograph: Screenshot.

The tagging mistakes may have been more acceptable to users if the auto-tagging feature was generally popular, but instead, the site’s devoted fan base has been complaining vocally since it was implemented on 7 May. A comment thread about the feature has racked up almost 2,500 replies, the vast majority of them negative.

Users complain that the tags are too broad or inaccurate to be useful, and some have questioned the site’s motivation in introducing the feature. Paul Hetheringon, the Flickr user who brought the offensive errors to the Guardian’s attention, says: “As so often in recent years, Flickr/Yahoo has implemented a significant and radical change in the user experience hastily and without consulting or even warning users. In this case they don’t seem to have considered the possible points of failure, and once again underestimated the anger of the user population at an unwanted change.

“At this point, they need to shut the auto-tagging down and remove all auto-tags from images until they can get the basics right.”

Tags on the photo of Dachau concentration camp. Photograph: Screenshot

Flickr responded to some user complaints, promising the ability to batch-edit tags, and explaining why the tags are generic. A Flickr staffer posted: “The overwhelming majority of searches on Flickr include some very general terms – sometimes alone and sometimes in conjunction with other, more specific terms. When people search Flickr, general tags often help in getting your photos found.”