The Export Frame dialog box opens with the name field
in text edit mode. The entire name is selected for editing. By default,
the frame name contains the name of the source clip or sequence,
and an auto-incremented number. For example, Premiere Pro names
frames exported from a clip named Clip.mov, "Clip.mov.Still001,"
"Clip.mov.Still002," "Clip.mov.Still003," and so on. Even if you rename
the frame, Premiere Pro uses the next number the next time you export a
frame from that same clip.
By default, Premiere Pro selects
the format last used for a frame export.