Avoid removing imgbuf and decoding the whole image again for reloads.

Using the same testing files as the previous patch,
the results are:

.---------------------------------------------.
|imgbufs     | No patch | Patch #1 | Patch #2 |
|----------------------------------------------
|1imgA.html  |   2/1    |   1/1    |    1/0   |
|2imgSA.html |   3/2    |   1/2    |    1/0   |
|3imgSA.html |   4/3    |   1/3    |    1/0   |
|----------------------------------------------
|2imgA.html  |   4/2    |   2/2    |    2/0   |
|3imgA.html  |   6/3    |   3/3    |    3/0   |
'---------------------------------------------'

n1/n2 means:
  n1 imgbufs were created for first load (empty cache)
  n2 imgbufs were created for reload (cached image)

Notes:
 * Rendering is much faster. Easy to notice with Back operation.
 * Between four to five times on www.welt.de.
 * Corner cases can be more than ten times. Usually, it *feels* faster.

1 files changed, 1 insertions, 3 deletions

diff --git a/dw/image.cc b/dw/image.cc
index 5df6b93e..e71c8f2f 100644
--- a/dw/image.cc
+++ b/dw/image.cc
@@ -425,9 +425,6 @@ void Image::setBuffer (core::Imgbuf *buffer, bool resize)
 {
    core::Imgbuf *oldBuf = this->buffer;
 
-   if (resize)
-      queueResize (0, true);
-
    if (wasAllocated () && needsResize () &&
       getContentWidth () > 0 && getContentHeight () > 0) {
       // Don't create a new buffer for the transition from alt text to img,
@@ -438,6 +435,7 @@ void Image::setBuffer (core::Imgbuf *buffer, bool resize)
       this->buffer = buffer;
       buffer->ref ();
    }
+   queueResize (0, true);
 
    DBG_OBJ_ASSOC_CHILD (this->buffer);