1) Creating a new file
Create new actionscript 2.0 > Modify > Document > Dimensions: 550 X 400 px > Frame Rate: 12fps for web and 24+ fps for Video.
2) Importing images to Flash
File > Import to library > Find and choose horse jpegs > Select all using shift button > Open.
3) Flash timeline basics
Create blank key frames for each
Drag JPEGS from the library in their number sequence to the stage for each individual blank keyframe.
Make sure they are at the same place on the stage as your previous JPEGS by using rulers.
View > Rulers
Once all JPEGS are in place like below