NetworkError when attempting to post pasted images

### Site

phanpy.social

### Version

2024.12.08.7e1ffc5

### Instance

_No response_

### Browser

Firefox Version 133.0 (64-bit) on Windows 10

### Bug description

Receive a "NetworkError when attempting to fetch resource." error when attempting to send a post with more than one copy-pasted image attached.

### To reproduce

1. Right-click copy a .jpg from any website.
2. Paste image into the compose box in Phanpy.
3. Copy a different image.
4. Paste second image into the compose box.
5. Attempt to send the post, receive NetworkError.

### Expected behavior

You should be able to post pasted images without errors.

### Other

I have never encountered this bug in other clients so it seems to be specific to Phanpy. In my experience it only happens when trying to post more than one pasted image, a single pasted image can be sent without any issue.

Reproduce the problem in Firefox on Windows by pasting two different JPG images into the compose box and sending the post. Trace the compose and post-send flow to find where multiple pasted images are handled; done means a post with more than one pasted image sends successfully without the NetworkError.

Written by the indexing model from the issue text.