Can I sue regarding a faulty seat belt?

1) You need proof that the seatbelt was defective as designed or manufactured (as oppposed to, say, a) becoming worn or damaged or over time, or b) you had not properly latched it). This would require more than pictures of the latch; it will require an examination by some engineer with relevant training and experience--who you would have to pay, and which can cost many hundreds to a few thousand dollars. The law requires expert testimony to explain how a device or fitting is defective and why.
2) If there is no good evidence of a defect in manufacture or design, you cannot win the case; the car builder is not responsible for anything that happens *after* they place the car in your hands, so you have to be able to prove (e.g. with the expert testimony discussed above) that the car (or seatbelt) manufacturer was at fault.
3) You can only sue for lost wages, out-of-pocket medical bills, and possibly some amount for "pain and suffering" to the extent you have not been compensated by insurance (e.g. medical insurance coverage costs) or worker's comp. To give a grosslly oversimpifed example: say that reasonable compensation for this would be $30,000, but you receive a total of $20,000 from insurance and workman's comp--you can only sue for and recover the extra $10,000.
Depending on how severe your injuries, how much work you miss, how much you incur in bills, etc., it may not be worth taking legal action.