There is no limit in uploading images or documents in MCC. However, the system only accepts .htm, .html files and I highly suggest that you create the message using the online editor.
But, if you need to, you can convert your Word message into a format that the system can read. To convert the message, open up Microsoft Word, and load your message. Next, go to file save and save the file as Web Page Filtered.
Now, use your newly saved message to upload into our system and you’re ready to go.
How to insert an image in the Message: https://help.mailclickconvert.com/faq/how-to-insert-an-image-in-the-message/
How to Upload a Document: https://help.mailclickconvert.com/faq/how-to-upload-a-document/