How do I search for .gif image on my S3?
GOOGLE GOGGLE app can Help to upload a image 
Google Search By Image APP

Open Google image in your Default or Chrome browser 

1st Method

type filetype:gif [your query] or inurl:gif [your query] then Tap Search

result will be in .gif format

2nd Method

Open Google image in your Default or Chrome browser 

then Tap More > Type > choose Animated