You must upload yours logo to the logo_mini or logo_big folders:
\\#\#\public_html\wp-content\uploads\phpleague\logo_mini\
\\#\#\public_html\wp-content\uploads\phpleague\logo_big\
For the players pictures is the same way:
\\#\#\public_html\wp-content\uploads\phpleague\players\
p.s. must be in .png file type
