Usually, a DSLR has a fixed maximum continuous shooting rate, and file size mainly affects how long it can maintain that speed before the buffer fills.

For the Canon 1100D, the quoted rates are about 2 fps in RAW and 3 fps in JPEG. So switching from RAW to JPEG can increase the burst rate, but lowering JPEG resolution will not increase it beyond the camera’s JPEG maximum of 3 fps.

What lower-resolution or more compressed JPEG settings can do is reduce data throughput, which may let the camera keep shooting at its top rate for longer before the buffer fills and the frame rate drops.

In general, burst rate is limited by the slowest part of the capture pipeline, which can include shutter/mirror mechanics, autofocus, sensor readout, image processing, buffer size, and card writing speed. So smaller files help only if data handling is the bottleneck; they cannot overcome the camera’s built-in maximum fps.