Hello. It appears both the current Android release and the K web interface share this bug on my side. I found it unnecessary to upload a screenshot because the issue is very easy to replicate if it is indeed a bug. But I am trying to send a picture of size 1113x42 pixels and neither the mobile application nor the web interface seem to deal with it well. I tried to send it after editing it in-app from a larger screenshot and it kept sending a black image to the other side. From desktop it simply refused to upload, with the clock icon never turning to a check icon on the message.
I considered this a bug and/or a lack of feature, therefore I am reporting it in hope it gets fixed and helps others. Because if I deem it necessary to send a single pixel image then your program should be able to handle it. I consider "sending an image" an atomic feature, regardless of image content; it is a 2D matrix of RGB values.
Telegram Web 1.4.3 K, Firefox 101, Android v8.7.4 (2636)