This topic has been widely discussed in the Inventor forums, but I still find users asking me how to do it, so I thought it would be prudent to post it for future reference. Even though I will be covering procedures for use in the title block of an Inventor drawing (.idw, .dwg), the procedures and options will be nearly identical for inserting an image into a part file. For now, let's assume the purpose for putting an image into a title block is to make the drawings we produce instantly recognizable, simple company branding. There are considerations for logo size, placement, colors, and more, which I will not address, but only the simple instruction on how to do it, so please don't make fun of my logo, or how I choose to use it.
First, I need to open up my company template drawing file in Invnentor, or create one. Where are the template files located anyway? You can locate them by either clicking on Tools > Application Options, and then selecting the File tab, or by clicking on the New button on the quick access toolbar (See images below).
In this example, I'm simply going to select the Standard.dwg template, in order to create from it, a brand new template file with my company logo. Once I have my file opened, I can expand the Drawing Resources folder and the Sheet:1 icon to see which title block is currently in use. I do this so I am sure to make edits to the correct title block resource.
I right-click on the ANSI - Large title block under the Drawing Resources folder and select Edit.
You are then placed into sketch mode, where you can make edits to the title block. (Images can only be placed into sketch mode.) Select Image from the Insert panel of the Sketch tab on the Ribbon. You are prompted to pick on a location or two corners to define the placement of an image. Browse for the image file to be inserted.
In the Open file dialog box, once your file is selected, be sure to un-check the box that says LINK. If you leave it checked, then the file acts like an xref and will always search to resolve the link. If the logo file is ever moved to another location or is deleted, Inventor will display the Resolve Link dialog box to have you resolve it, if possible. By unchecking the box, the image is embedded into the title block with no reference to an outside link.
Once the image file is inserted, right-click and select Done. You can then use the grip handles to reposition and scale it to the desired location. Click Finish Sketch and choose Yes to save edits, or choose Save As... to create an entirely new title block resource. Finally, do a Save As > Save Copy As Template, to save the template file into your templates directory.