[Enhancement] Enforce 5MB Image Upload Limit

[epamLDadayan]

[Enhancement] Enforce 5MB Image Upload Limit

📋 Description

Implement 5MB file size limit specifically for image uploads while maintaining 150MB limit for other file types. Prevent oversized images at upload time rather than failing at LLM call.

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🎯 User Story

As a user uploading images to chat
I want clear feedback when my image exceeds the size limit
So that I can resize it before sending rather than getting cryptic errors

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💼 Business Value

• Better UX: Prevent uploads upfront instead of failing at LLM call
• Clear Messaging: No more "Internal SDK Error" for oversized images
• Cross-Model Compatibility: 5MB works with all LLM providers (Anthropic, OpenAI, etc.)

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🔑 Requirements

File Size Limits

File Type	Max Size
Images (.jpg, .jpeg, .png, .gif, .webp, .svg, .bmp)	5MB
All other files	150MB (unchanged)

Limit Scope

• Per image: Each individual image limited to 5MB
• Per conversation: No limit (unchanged)
• Other files: Keep existing 150MB limit

Upload Methods Affected

• File picker upload
• Drag & drop
• Copy/paste
• All image upload entry points

Existing Limitations

• Keep all current file type restrictions
• Keep all current conversation attachment limits
• No changes to non-image file handling

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✅ Acceptance Criteria

AC1: Image Upload Blocked at 5MB

Given I try to upload an image larger than 5MB
When I use any upload method (picker, drag/drop, paste)
Then upload is blocked immediately
And I see error: "Image exceeds 5 MB limit. Please resize and try again."

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AC2: Multiple Images Validation

Given I upload multiple images at once
When some images exceed 5MB
Then only oversized images are rejected
And valid images proceed normally
And error lists rejected files: "The following images exceed 5 MB limit: [filename1.jpg, filename2.png]"

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AC3: Other Files Unchanged

Given I upload a non-image file (PDF, DOCX, etc.)
When the file is under 150MB
Then upload proceeds normally
And 5MB limit does not apply

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AC4: Regenerate with Oversized Image

Given a conversation has an existing image over 5MB (legacy)
When I try to regenerate the message
Then I see error: "Image exceeds 5 MB limit. Please remove or replace the image."

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🎨 Error Messages

Single Image Upload

⚠️ Image exceeds 5 MB limit. Please resize and try again.
   File: screenshot.png (13.2 MB)

Multiple Images

⚠️ The following images exceed 5 MB limit:
   • large_photo.jpg (8.5 MB)
   • screenshot.png (13.2 MB)
   
   Please resize and try again.

Regenerate Attempt

⚠️ Image exceeds 5 MB limit. Please remove or replace the image to continue.

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📌 Notes

• No migration needed for existing conversations
• Legacy oversized images remain but will fail on regenerate
• 5MB aligns with Anthropic's limit (strictest among providers)
• Validation happens client-side for immediate feedback

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🔗 Related

• Bug: Generic "Internal SDK Error" for Anthropic 5MB limit - [BUG] Generic "Internal SDK Error" displayed when uploading images exceeding 5MB limit for Anthropic models #3622
• Anthropic API limit: 5MB per image
• Stage example: conversation [BUG] Incorrect Sorting of Tools in Dropdown List for "Function" Node #948