Welcome to the forum.
Your "blurry pictures" could be the result of several factors.
As you have Video, did you choose a Project Preset, that matched that Video perfectly?
Then, did you Scale the Still Images to match the Frame Size of the Preset, in Photoshop, Photoshop Elemens, or similar, before you Imported them? This is very important.
Did you Render your Timeline, by hitting Enter/Return, before you viewed the Timeline?