The Sun's photosphere approximates a black body. The light it
emits approximates blackbody radiation. That is, a continuous
spectrum, with intensity at different wavelengths dependant on
temperature. The intensity of a blackbody spectrum at any
wavelength, over the entire continuum, is given by Plank's
radiation law. The peak wavelength of that intensity curve is
given by the simpler Wien's displacement law.
The Sun's photosphere is hottest at the bottom and cooler at the
top. The chromosphere, above the photosphere, is even cooler.
Cooler ions in and above the photosphere absorb some of the
emitted blackbody radiation at specific wavelengths. The result
is dark lines in the otherwise continuous spectrum:
http://www.noao.edu/image_gallery/images/d5/suny.jpg
Different ions absorb different wavelengths, and each different
ion absorbs many specific wavelengths, so there is a very large
number of dark lines in the Sun's spectrum. The image above
shows just the visible light part of the spectrum. There are
similar lines in the infrared, ultraviolet, and X-ray portions
of the spectrum.
If the ions are hotter, rather than cooler, they can emit more
light than they absorb, causing bright lines instead of dark
lines. Ions in the Sun's upper atmosphere are often heated by
extremely powerful magnetic fields to very high temperature,
causing them to emit light in specific bright lines. The higher
the temperature, the shorter the wavelength of the specific
lines which are bright. Wavelengths which are shorter or longer
than those specific wavelengths will have dark lines.
Emissions given off by the Sun's photosphere, a lightbulb, a
burning candle, your body, and an ice cube all resemble blackbody
curves fairly closely.
The sun's chromosphere, emission nebulae, fluorescent lights,
neon lights, LEDs, lasers, dental X-ray machines, TV screens,
and computer monitors all give off light with spectral curves
completely unlike blackbody curves, instead conststing mostly
of bright line emission at specific wavelengths. That is what
you see in the narrow-passband images from the TRACE spacecraft:
Mostly light from bright-line emission, plus some light from
blackbody emission at the same wavelength.
What has confused you is the fact that bright-line emission
does not occur at a specific wavelength if the temperature
is too high. You are attempting to ascribe a property of
blackbody emission to bright-line emission.
-- Jeff, in Minneapolis