Copy below
input the folda u uploaded your files in the place UPLOADS then if you wnt each file to have its preview image jst lyk the screenshot above then you create a folda name Games Images upload the preview image you wnt to use and rename according to its filename then add .png after the filename
EG: If you uploaded a file named Real_Football_2017.jar you rename its image to Real_Football_2017.jar.png
NOTE: If You Dont Rename It According To Its Filename It Will Not Work, In Any case You Uploaded A File Pes 2016.jar And The Preview Image You Rename To Pes_2016.jar.png or pes 2016.jar.png It Will Not Work Reason Its Not According To Its Filename It Should Be In Dis Format Pes 2016.jar.png
Thats It!
(Edited by 2017-04-06 05:28 STRIKELORD )