Behind an HTTP proxy (e.g. tgapi.indevs.in) the PTB
media_write_timeout (~20s) is exceeded by raw PNGs > 1-2MB, causing
TimedOut errors on both send_photo and the send_document fallback.
Add TelegramAdapter._compress_image_to_jpeg() which converts large
PNG/raster images (>1MB) to progressive JPEG at 85% quality, with
optional resize above 1600px. Applied in send_image_file() and in the
media-group path of send_multiple_images(). Compression is a no-op for
JPEGs, small files, and non-raster formats, and falls back gracefully
if Pillow is unavailable.
Co-authored-by: user
fc73bb462e