What is the ruling of uploading old pictures of ourselves not covering our awrah?
According to Imam al-Nawawi, the ruling of looking at the awrah of an ajnabi, whether it is for man or woman is haram according to the ijma’ of scholars.  As for looking at a printed or digital picture, it can be analogically deduced (qiyas) to be the same as the reflection of an object on a mirror or water that has been discussed by scholars.
Imam al-Ramli when commenting on the opinion of Imam Nawawi in al-Minhaj where it is stated, it is prohibited for a man to look at the awrah of a free ajnabi woman, but it isn’t prohibited if the awrah is just an image, picture or reflection. Then, it isn’t prohibited to look at the awrah through a mirror as stated in the fatwa issued by some scholars for it isn’t considered to be looking at the awrah directly. However, the permissibility is only applicable for as long as it doesn’t lead to fitnah. 
Concurrently, the wara’ attribute and being cautious should be prioritized. The potential that the old picture of when a person isn’t covering his awrah (although now he has covered his awrah properly) to lead to fitnah is very high. Hence, here is the basis of its prohibition according to the Islamic legal maxim sadd al-zari’ah which is to prevent permissible matters that could lead to haram. This is also in accordance with another maxim which states:
ما أدى إلى الحرام فهو حرام
“Whatever leads to haram is haram.”
And also based on another maxim:
اتَّقُوا مَواضِعِ التُّهَمِ
“Be careful of the opportunities of reproach.”
In whatever situation where there is a risk of fitnah, one should try his best to avoid it for it will have a negative effect whether it is in the short or long-term. Any form of picture can be manipulated for bad intentions and one should really put his consideration before uploading his pictures. Especially in our current times where one is easily exposed to danger which includes the issue which involves paedophiles, sexual predators and others. Wallahu a’lam.
 Sharḥ al-Nawawī ʿalā Muslim, 4/30
 Nihāyat al-Muḥtāj, 6/187; Iʿānat al-Ṭālibīn, 3/301.