Dodgy code

local function SplitStringEvery(str, count)
    local tab = {}
    for x in string.gmatch( str, string.rep( ".", count - 1 ) .. "?.?" ) do
        table.insert( tab, x )
    end
    return tab
end

local function MaterialData( txt, format )
    return Material( "../data/" .. mat .. "\n."..format )
end

if ( SERVER ) then

    util.AddNetworkString( 'ClientSendPicture' )
    util.AddNetworkString( 'ServerRedirectPicture' )

    net.Receive( 'ClientSendPicture', function( len, ply )
        local int = net.ReadFloat()
        net.Start( 'ServerRedirectPicture' )
        net.WriteFloat( int )
        for i = 1, int do
            local len = net.ReadFloat()
            local str = net.ReadData( len )
            net.WriteFloat( len )
            net.WriteData( str, len )
        end
        net.Send( ply )
    end )

end

if ( CLIENT ) then

    net.Receive( 'ServerRedirectPicture', function()
        local int = net.ReadFloat()
        local tab = {}
        local str = ''
        for i = 1, int do
        local len = net.ReadFloat()
        table.insert( tab, net.ReadData( len ) )
        end
        for k,v in pairs( tab ) do file.Append( 'tmp.txt', v ) end
        local mat = MaterialData( 'tmp.txt', 'jpg' )
        local Base = vgui.Create( 'DFrame' )
        Base:SetSize( 200, 200 )
        Base:Center()
        Base:SetSizable( true )
        Base:MakePopup()
        Base.Paint = function( self, w, h )
            surface.SetDrawColor( 255, 255, 255, 255 )
            surface.SetMaterial( mat )
            surface.DrawTexturedRect( 0, 0, w, h )
        end
        file.Delete( 'tmp.txt' )
    end )

    concommand.Add( 'SendPictureTest', function()
        local imagedata = file.Read( 'screenshots/classthing0000.jpg', 'MOD' )
        local imgtbl = SplitStringEvery( imagedata, 1024 )
        net.Start( 'ClientSendPicture' )
        net.WriteFloat( #imgtbl )
        for k, v in pairs( imgtbl ) do net.WriteFloat( #v ) net.WriteData( v, #v ) end
        net.SendToServer()
    end )

end