Why Firefox crashes when using it while working with Gimp?

I am currently using Ubuntu 18.04.1 and Gimp 2.10 and Firefox is updated to its last version Mozilla Firefox 62.0.3

I have a serious issue, while I am working on a photo edition using Gimp, and then I open two or more tabs, suddenly my screen freeze or Firefox crashes.

What can I do to avoid this?

Is is due to I use only one work-space? Is it a memory issue?

I show you here my free -m out put while I am using gimp and Firefox and brave all together...

 free -m
              total        used        free      shared  buff/cache   available
Mem:           1984        1572          99         143         312         110
Swap:          2047         469        1578

Thanks in advance