This dream seems to reflect your feelings about letting go of the past and the memories associated with your mom. Burning old pictures typically symbolizes a desire to release or transform something that holds emotional weight. In your case, it might indicate that you are processing your relationship with your mother, perhaps acknowledging the importance of those memories while also recognizing the need to move forward.
The act of burning the pictures could signify a form of closure or acceptance, suggesting that you appreciate the experiences and what they meant to you, but you may also feel the need to release them to fully embrace the present. The fact that there are some pictures you couldn't burn indicates that there are certain memories or emotions you may not be ready to let go of just yet, which is completely natural.
This dream invites you to reflect on your feelings regarding your past and your relationship with your mother. It encourages you to think about what memories you cherish and which ones you feel ready to release. It's okay to take your time with this process; it's a personal journey and can be done at your own pace. Consider what aspects of your past you want to hold onto and what you might be ready to transform or let go of.