That question is very confusing. Anyway, if you are looking for a thumbnail generator that works on FLV video files, you can try SMPlayer. It is a free media player that works on Microsoft Windows and Linux. Aside from being a media player and play media files such as AVI, MP4, MPG, MP3, and others, it is also capable of generating thumbnails for a video.
To download, visit SMPlayer – Free Media Player. It supports Windows XP, Windows Vista, Windows 7, Windows 8.x, and Windows 10 as well as Linux. One interesting fact about this media player is that, it can remember the settings of all the files you played. It also features the resume function.
When you open a previously played movie, it can remember and resume at the point where you left off plus with the same settings like the audio track, volume, subtitles, and others. SMPlayer is the GUI or the graphical user interface for the award-winning MPlayer, one of the best media players in the world capable of playing almost all known audio and video formats. It uses the MPlayer as playback engine.
To generate a thumbnail from a video, load the video in SMPlayer then click “Video” and then “Thumbnail Generator”. Configure the settings in the dialog then click “OK”.