I'm not sure what you mean by too big, do you mean the file size?
The picture and image controls in Access allow you to crop and zoom etc on a picture so that it will fit the image box.
I had to open a picture from Access for an application I wrote for a medical department, but I created a seperate application using Visual Basic 6. This opened allowed the consultants to draw squiggly lines on the picture and close it. It was then refereced by the database. Doing it that way is hard work, stick with the picture controls - it's easier.