There is a way but you may not like it , but worth a shot.
Open a Blank Word file
Use the insert image or add image activity to add one image to the word document
You may have to add an enter or ctrl+enter action to add a new page to the word document and repeat the process of inserting the image to each page
Then from File menu > Export > Save as XPS/PDF document - It will open in a Browser in this case
Alternately, I think there is Save As PDF activity in the UiPath Word Automation package
Save the .pdf file as .TIFF file - You can do this by opening the PDF using Start Application and then using the File Save As to save it with a .TIFF extension