1500281 - Clipboard screenshot results lead to invalid images on github/Slack, …

Status: NEW

(DevTools :: Console, defect, P2)

Description

[:Harald Kirschner :digitarald]

STR:
- Take a screenshot using the console command `:screenshot --clipboard`
- Open a github issue on any project
- Cmd-V, paste the clipboard to upload an image (for example https://github.com/devtools-html/debugger.html/issues)
- Switch to Issue preview to see image

ER: Image is uploaded and shown correctly.
AR: Image has errors and is not rendered.

Pasting all other image sources work, I never experienced this erroneous upload before. Pasting the same clipboard content into OSX's Preview app works.

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

Attachment: error message

I reproduce this as well. Github prints an error message saying that the file is too big (>10MB), but when saving the screenshot, it's under < 300KB in my test case.

I couldn't debug what's happening on GH since sourcemap seems broken, and a full project search seems to run forever.

After running `:screenshot --clipboard`, if I paste into a github issue on Chrome, then it's fine, so my guess it's not an issue with the screenshot command, but either with Firefox or Github.

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

Setting this as P1 since I think it's a pretty common workflow.

I also reproduce on DevEdition, but there's something funny: if I run the screenshot command in DevEdition, then paste into github on Nightly, then it does upload the file.

Next, I tried to screenshot with a very small content page, and the upload did seem to work, but the resulting png seems corrupt ? https://user-images.githubusercontent.com/578107/47201770-46f99500-d37b-11e8-9371-1d46605f970c.png

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

cc yulia since she might have an idea about what's going on

Comment 4

[Yulia Startsev [:yulia] OOO until July 2026]

not sure it is related... but I keep getting the following error: Attempt to set a forbidden header was denied: Connection

I will keep looking into it

Comment 5

[Nicolas Chevobbe [:nchevobbe]]

Uploading on Slack does technically work, but the file is HUGE (17MB) and seems corrupt https://files.slack.com/files-pri/T3V7H1198-FDKC4UYES/image.png