feat: update Image field to match File

Author: guillaq

workflowai/core/fields/image.py

@@ -1,10 +1,5 @@
-from pydantic import BaseModel, Field
+from workflowai.core.fields.file import File
 
 
-class Image(BaseModel):
-    name: str = Field(..., description="An optional name for the image")
-    content_type: str = Field(..., description="The content type of the image", examples=["image/png", "image/jpeg"])
-    data: str = Field(..., description="The base64 encoded data of the image")
-
-    def to_url(self) -> str:
-        return f"data:{self.content_type};base64,{self.data}"
+class Image(File):
+    pass