compress the following image data

[Madammar]

i have Jpeg image that loaded into memory stream and later on i use TIdEncoderMIME To encode the stream to a base64 string 

with the following code 

Code:

try
    JpegStream := TMemoryStream.Create;
    try
      Jpg := TJPEGImage.Create;
      try
        Jpg.Performance := jpBestSpeed;
        Jpg.ProgressiveEncoding := True;
        Jpg.ProgressiveDisplay := True;
        Jpg.Assign(btmpcam);
        Jpg.CompressionQuality := Qualitycm;
        Jpg.Compress;
        Jpg.SaveToStream(JpegStream);
      finally
        Jpg.Free;
      end;
      JpegStream.Position := 0;
      StringImageData := TIdEncoderMIME.EncodeStream(JpegStream);
    finally
      JpegStream.Free;
    end;

but the output base64 string length is 4000 which is too big. is there any way to compress this string to get smaller length ?

i already used zlib to compress the  StringImageData with the following code 

Code:

interface
uses
  Classes, SysUtils, zlib, EncdDecd;


function ZCompressString(aText: string; aCompressionLevel: TCompressionLevel): string;
function ZDecompressString(aText: string): string;


implementation

function ZCompressString(aText: string; aCompressionLevel: TCompressionLevel): string;
var
  strInput,
  strOutput: TStringStream;
  Zipper: TZCompressionStream;
begin
  Result:= '';
  strInput:= TStringStream.Create(aText);
  strOutput:= TStringStream.Create;
  try
    Zipper:= TZCompressionStream.Create(aCompressionLevel, strOutput);
    try
      Zipper.CopyFrom(strInput, strInput.Size);
    finally
      Zipper.Free;
    end;
    Result:= strOutput.DataString;
  finally
    strInput.Free;
    strOutput.Free;
  end;
end;


function ZDecompressString(aText: string): string;
var
  strInput,
  strOutput: TStringStream;
  Unzipper: TZDecompressionStream;
begin
  Result:= '';
  strInput:= TStringStream.Create(aText);
  strOutput:= TStringStream.Create;
  try
    Unzipper:= TZDecompressionStream.Create(strInput);
    try
      strOutput.CopyFrom(Unzipper, Unzipper.Size);
    finally
      Unzipper.Free;
    end;
    Result:= strOutput.DataString;
  finally
    strInput.Free;
    strOutput.Free;
  end;
end;

but image got corrupted after decompression what is the correct way to compress the output data string ?