Re: how to upload a picture from a text into my gallery
You don't put pictures into the gallery, you put them on the phone, and Gallery shows all pictures on the phone.
If you want a separate album, albums in Gallery are folders on the phone. So create a folder (use a file manager app - Files, My Files, whatever your phone comes with) and create a folder with the name you want the album to have. Put your pictures in there. (It may take a restart until the phone "notices" the new album.) If you put a folder inside a folder, the album name is the last folder, so pictures in DCIM/Camera/My Pictures will show up in the album My Pictures. (That can get confusing if you have 2 folders with the same name in different places, like DCIM/Camera/My Pictures and DCIM/My Pictures.)