gpt-4o-image vs grok-4-fast-reasoning

OpenAI gpt-4o-imagexAI grok-4-fast-reasoning
VendorOpenAIxAI
Context window—2,097,152
Max output—30,000
ReasoningNoYes
Tool callingNoYes
File inputNoYes
Inputtexttext, image
Outputimage, texttext
Released—2025-08-27