Image rendering fails when running inside tmux

[elainefs]

Describe the bug
Images are rendered correctly when running mastui directly in the Kitty terminal. However, when running mastui inside a tmux session within Kitty, images fail to render, even with the necessary tmux configurations for image passthrough.

To Reproduce

1. Open Kitty terminal.
2. Start a tmux session: tmux.
3. Run mastui.
4. Navigate to a post containing an image.
5. Observe that the image is missing, replaced by a empty space.

Expected behavior
Since the image is rendered normally directly in the Kitty terminal, and the allow-passthrough setting is enabled in tmux, the image should be rendered inside the tmux session.

Screenshots

On the left, mastui running directly in Kitty terminal. On the right, running inside tmux.

Desktop (please complete the following information):

• OS: Debian 13
• Terminal: Kitty (v0.41.1)
• tmux version: 3.5a

[kimusan]

Hi, This is a known limitation in tmux and I have no good solution for it.

[elainefs]

Hi!

But other tools, like image.nvim, render images perfectly in this same setup (kitty + tmux).

Perhaps some adjustment is needed in the image escape sequences (\ePtmux;\e ... \e\) when a multiplexer is detected?

I don't know much about this, I saw something related in this link: https://unix.stackexchange.com/questions/556738/how-can-i-send-an-escape-sequence-from-a-nested-tmux-session-to-iterm2

So probably I am talking nonsense.

Thanks for the great work on the tool!