Fastest way to get an image from Skitch into OmniFocus?
AFAIK, you can't do it without AppleScript. 

Here is my way to do this:

on adding folder items to this_folder after receiving added_items
    try
        repeat with i from 1 to number of items in added_items
            set this_item to item i of added_items
            tell application "Finder" to set file_name to (name of this_item)
            tell application "OmniFocus"
                tell quick entry
                    open
                    set NewTask to make new inbox task with properties {name:file_name}
                    tell the note of NewTask
                        make new file attachment with properties {file name:this_item, embedded:true}
                    end tell
                    activate
                end tell
            end tell
        end repeat
    end try
end adding folder items to



Save this AppleScript to /Library/Scripts/Folder Action Scripts/Add File To Omnifocus.scpt You must use root access. (Download script)
Create a folder under your Documets folder
Right-click on this folder, and select Services>Folder Actions Setup
Select the "Add File To Omnifocus" script


Now you can drop any file to this folder(I keep it in my Dock) and it automatically create a QuickEntry Task with embedded attachment.

I hope this could help you.