Is this an example of a weak chin? If so, are there any options other than surgery to help make the chin more prominent? (photo)

It looks that you would benefit from chin augmentation. In your case chin implant would be the best solution. However, chin augmentation with fillers as well as fat grafts is available as well. Good luck.

Yes, a chin implant could improve the shape and projection of your chin. When well placed by an expert, a chin implant can last for decades or a lifetime. You can choose a chin with will give you a better projection and smooth the jawline. A consultation with a board-certified facial plastic surgeon is important; for the patient to be evaluated, their goals discussed, and a custom treatment plan decided upon. I hope this helps.

Your photograph does demonstrate some recession of your chin.  An alternative to surgery would be using injectable fillers to augment the chin and make it more pronounced.  This can help to add balance to the profile.  

  Placement of fillers in this area is only temporary, and does not work very well.  Placement of the surgical chin implant in this location works quite well.   For many chin implant examples and more information, please see the link and the video below

 Hi, I have performed many facial shaping procedures, including Chin Augmentation with dermal fillers or silastic chin implants, for over 30 years.  From the photo, your chin is very weak.  When the chin is weak, this creates an imbalance making the nose appear larger, the mid face top heavy, the lower face looks short, de-emphasizes the lips and allows early formation of a "double chin".  
 Proper placement of a silastic chin implant adds forward projection to the chin thereby creating harmony and balance to the lower face.  Using the same incision, liposuction can be performed to reduce the fat and further shape the neck.  Excess skin, from below the chin, can also be removed through the same incision.  
 I have found that placement of a silastic chin implant, through a small curved incision under the chin (also allows excess skin removal) to be very safe, quick, highly effective and far less invasive than a sliding genioplasty (requires extensive tissue dissection, bone cuts and placement of metal screws and plates to secure the cut segments of bone).  I perform chin implant surgery in 30 minutes or less, often using a local anesthetic alone.  In my opinion, you are a good candidate for chin implant surgery.  You can augment your chin with precise placement of an "off the shelf" dermal filler (I prefer Restylane Lyft).  This will be far less "cost effective" over the years.  Fat should be avoided for the reasons explained below. I have performed many facial shaping procedures using dermal fillers, facial silastic implants, liposuction and facelifts for over 30 years.  In my experience and despite its recent increase in popularity, fat transfer (fat injection) offers "far" less of a reliable and predictable volume for facial shaping than an off the shelf dermal filler or facial implant.  For that reason, I do not use fat to shape the cheeks, chin, lips or jaw line.  Tissue physiology is quite simple.  Tissue requires a blood supply in and out as well as lymphatic connections to remain viable and alive.  Once fat is removed from the body all of these things have been disrupted.  Just because the removed fat is mixed with PRP or something else doesn't make the blood and lymphatics magically re-appear.  The fat at that point is not living tissue which means that it's prone to being dissolved by the body (most likely in an uneven and unpredictable manner).  Injecting fat back into the face does not create the required elements to make the fat living tissue once again.  So the argument that fat is alive and viable in the face once it's been removed and re-injected makes no sense to me as a physician and surgeon.
 The other issue that I have with fat transfer is the lack of precision.  Fat is thick by nature which means it's not the same consistency as an off the shelf dermal filler.  Fat injections use an increased volume injected in an attempt to compensate for the volume loss that "will" happen.  This means a lack of specific shape and volume that simply can not begin to compare with the specificity of using a silastic facial implant of a "known" shape and volume.  In that regard fat offers too much of an unknown to make it a reliable and predictable method for facial shaping.  There's a significant difference between a 3mm and 5mm thick cheek implant.  You can imagine the magnitude of difference there is between retaining 60% of 25cc's of fat versus 35%.  In my humble opinion, I just don’t see how fat could possibly be used to precisely shape facial features?
Hope this helps.