formdata:=TIdMultiPartFormDataStream.Create; // создаем переменную пост запрсоа
formData.AddFile('new_photo', '123.jpg', 'image/jpeg');
formData.AddFormField('act', 'nadd');
formData.AddFormField('from', 'nfile');
cod:=idhttp1.post('сайт', formData);
formData.Free;

POSTDATA =-----------------------------21624280192125
Content-Disposition: form-data; name="act"

add
-----------------------------21624280192125
Content-Disposition: form-data; name="from"

file
-----------------------------21624280192125
Content-Disposition: form-data; name="new_photo"; filename="123.jpg"
Content-Type: image/jpeg

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