Theoretically you can, if you have an advanced degree in machine vision, but not directly.
You cannot, but there are web apps and matlab code which can give you a keen approximation of what you want (I dont know what goes on under the hood exactly but I think that they just generate false 3D data from your images, the matlab code generates false surfaces using clustering to generate 'iso' surfaces which I think are okay for 3D printers).
Why you cannot?
Any 3D model (.off, .stl) is a point cloud model, that is, it is a collection of 3D point data. It can be generated via many techniques, for eg. LiDAR scanning is one of them and even then you have to set up a machine to scan an area continuously (sometimes from many viewpoints /orientatons depending on your method and accuracy required) to obtain approximate 3D information. I'm trying to tell you just how difficult it is to acquire 3D data.
Now a gif image (like any other image file) only has 2D image data in form of pixel intensities. There are ways to get exact 3D point clouds from single images but this is itself an area which is still under research
The web apps I spoke of:
For JPEG to GIF conversion (as an intermediate step), I dont know if you're on linux or Windows, but in linux you can use imagemagik to simply batch convert as:
convert *.gif *.jpeg
convert *.gif *.jpg
If you read in the reference below you can write an m file with the given library to do all the intermediate conversions within matlab itself.