Your size is very small and really not ideal.
Editing downloaded web stills is not ideal either.
For a Meeting??? Is this playing off the computer hard drive or a DVD?
If you have HD video and Low res stills – you got a mess.
Start with a Standard SD sequence, an easy setup like NTSC DV48k Anamorphic.
Make sure the frame rate and fields match the HD video.
Re-size the HD vid to fit in the sequence.
When the edit is done, change sequence codec to Prores 422.
Re-render all. Fully.
Export using current settings. Take that file into compressor to create your deliverables.
Chris Tompkins
Video Atlanta LLC