I just found the following in my logfile, after trying to upload a Conpherence image from within the website itself (i.e. dragging and dropping an image from my Phabricator instance website into the upload field of Conpherence, without saving it locally)
```
PHP message: [2015-05-05 19:11:16] ERROR 2: imagecreatefromstring(): Data is not in a recognized format at [/opt/phabricator/phabricator/src/applications/files/PhabricatorImageTransformer.php:198]
PHP message: arcanist(head=master, ref.master=8919a9c5b55e), libphremoteuser(head=master, ref.master=1def4e2d7f07), phabricator(head=master, ref.master=92d399d086c9), phutil(head=master, ref.master=cb8cdccb1a50), sprint(head=master, ref.master=53f16c2f6fa0)
PHP message: #0 imagecreatefromstring(string) called at [<phabricator>/src/applications/files/PhabricatorImageTransformer.php:198]
PHP message: #1 PhabricatorImageTransformer::getPreviewDimensions(PhabricatorFile, integer) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:112]
PHP message: #2 PhabricatorEmbedFileRemarkupRule::renderImageFile(PhabricatorFile, PhabricatorObjectHandle, array) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:47]
PHP message: #3 PhabricatorEmbedFileRemarkupRule::renderObjectEmbed(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:114]
PHP message: #4 PhabricatorObjectRemarkupRule::renderObjectEmbedForAnyMedia(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:368]
PHP message: #5 PhabricatorObjectRemarkupRule::didMarkupText() called at [<phutil>/src/markup/engine/PhutilRemarkupEngine.php:292]
PHP message: #6 PhutilRemarkupEngine::postprocessText(array) called at [<phabricator>/src/infrastructure/markup/PhabricatorMarkupEngine.php:138]
PHP message: #7 PhabricatorMarkupEngine::process() called at [<phabricator>/src/applications/conpherence/ConpherenceTransactionRenderer.php:59]
PHP message: #8 ConpherenceTransactionRenderer::renderTransactions(PhabricatorUser, ConpherenceThread, boolean, string) called at [<phabricator>/src/applications/conpherence/controller/ConpherenceViewController.php:70]
PHP message: #9 ConpherenceViewController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:218]
PHP message: #10 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:132]
PHP message: #11 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:19]
PHP message: [2015-05-05 19:11:16] ERROR 2: imagesx() expects parameter 1 to be resource, boolean given at [/opt/phabricator/phabricator/src/applications/files/PhabricatorImageTransformer.php:200]
PHP message: arcanist(head=master, ref.master=8919a9c5b55e), libphremoteuser(head=master, ref.master=1def4e2d7f07), phabricator(head=master, ref.master=92d399d086c9), phutil(head=master, ref.master=cb8cdccb1a50), sprint(head=master, ref.master=53f16c2f6fa0)
PHP message: #0 imagesx(boolean) called at [<phabricator>/src/applications/files/PhabricatorImageTransformer.php:200]
PHP message: #1 PhabricatorImageTransformer::getPreviewDimensions(PhabricatorFile, integer) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:112]
PHP message: #2 PhabricatorEmbedFileRemarkupRule::renderImageFile(PhabricatorFile, PhabricatorObjectHandle, array) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:47]
PHP message: #3 PhabricatorEmbedFileRemarkupRule::renderObjectEmbed(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:114]
PHP message: #4 PhabricatorObjectRemarkupRule::renderObjectEmbedForAnyMedia(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:368]
PHP message: #5 PhabricatorObjectRemarkupRule::didMarkupText() called at [<phutil>/src/markup/engine/PhutilRemarkupEngine.php:292]
PHP message: #6 PhutilRemarkupEngine::postprocessText(array) called at [<phabricator>/src/infrastructure/markup/PhabricatorMarkupEngine.php:138]
PHP message: #7 PhabricatorMarkupEngine::process() called at [<phabricator>/src/applications/conpherence/ConpherenceTransactionRenderer.php:59]
PHP message: #8 ConpherenceTransactionRenderer::renderTransactions(PhabricatorUser, ConpherenceThread, boolean, string) called at [<phabricator>/src/applications/conpherence/controller/ConpherenceViewController.php:70]
PHP message: #9 ConpherenceViewController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:218]
PHP message: #10 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:132]
PHP message: #11 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:19]
PHP message: [2015-05-05 19:11:16] ERROR 2: imagesy() expects parameter 1 to be resource, boolean given at [/opt/phabricator/phabricator/src/applications/files/PhabricatorImageTransformer.php:201]
PHP message: arcanist(head=master, ref.master=8919a9c5b55e), libphremoteuser(head=master, ref.master=1def4e2d7f07), phabricator(head=master, ref.master=92d399d086c9), phutil(head=master, ref.master=cb8cdccb1a50), sprint(head=master, ref.master=53f16c2f6fa0)
PHP message: #0 imagesy(boolean) called at [<phabricator>/src/applications/files/PhabricatorImageTransformer.php:201]
PHP message: #1 PhabricatorImageTransformer::getPreviewDimensions(PhabricatorFile, integer) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:112]
PHP message: #2 PhabricatorEmbedFileRemarkupRule::renderImageFile(PhabricatorFile, PhabricatorObjectHandle, array) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:47]
PHP message: #3 PhabricatorEmbedFileRemarkupRule::renderObjectEmbed(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:114]
PHP message: #4 PhabricatorObjectRemarkupRule::renderObjectEmbedForAnyMedia(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:368]
PHP message: #5 PhabricatorObjectRemarkupRule::didMarkupText() called at [<phutil>/src/markup/engine/PhutilRemarkupEngine.php:292]
PHP message: #6 PhutilRemarkupEngine::postprocessText(array) called at [<phabricator>/src/infrastructure/markup/PhabricatorMarkupEngine.php:138]
PHP message: #7 PhabricatorMarkupEngine::process() called at [<phabricator>/src/applications/conpherence/ConpherenceTransactionRenderer.php:59]
PHP message: #8 ConpherenceTransactionRenderer::renderTransactions(PhabricatorUser, ConpherenceThread, boolean, string) called at [<phabricator>/src/applications/conpherence/controller/ConpherenceViewController.php:70]
PHP message: #9 ConpherenceViewController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:218]
PHP message: #10 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:132]
PHP message: #11 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:19]
PHP message: [2015-05-05 19:11:16] ERROR 2: Division by zero at [/opt/phabricator/phabricator/src/applications/files/PhabricatorImageTransformer.php:204]
PHP message: arcanist(head=master, ref.master=8919a9c5b55e), libphremot
[Tue May 05 19:11:16.662984 2015] [proxy_fcgi:error] [pid 26102] [client <…>] AH01071: Got error 'd=master, ref.master=53f16c2f6fa0)
PHP message: #0 PhabricatorImageTransformer::getPreviewDimensions(PhabricatorFile, integer) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:112]
PHP message: #1 PhabricatorEmbedFileRemarkupRule::renderImageFile(PhabricatorFile, PhabricatorObjectHandle, array) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:47]
PHP message: #2 PhabricatorEmbedFileRemarkupRule::renderObjectEmbed(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:114]
PHP message: #3 PhabricatorObjectRemarkupRule::renderObjectEmbedForAnyMedia(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:368]
PHP message: #4 PhabricatorObjectRemarkupRule::didMarkupText() called at [<phutil>/src/markup/engine/PhutilRemarkupEngine.php:292]
PHP message: #5 PhutilRemarkupEngine::postprocessText(array) called at [<phabricator>/src/infrastructure/markup/PhabricatorMarkupEngine.php:138]
PHP message: #6 PhabricatorMarkupEngine::process() called at [<phabricator>/src/applications/conpherence/ConpherenceTransactionRenderer.php:59]
PHP message: #7 ConpherenceTransactionRenderer::renderTransactions(PhabricatorUser, ConpherenceThread, boolean, string) called at [<phabricator>/src/applications/conpherence/controller/ConpherenceViewController.php:70]
PHP message: #8 ConpherenceViewController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:218]
PHP message: #9 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:132]
PHP message: #10 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:19]
PHP message: [2015-05-05 19:11:16] ERROR 2: Division by zero at [/opt/phabricator/phabricator/src/applications/files/PhabricatorImageTransformer.php:204]
PHP message: arcanist(head=master, ref.master=8919a9c5b55e), libphremoteuser(head=master, ref.master=1def4e2d7f07), phabricator(head=master, ref.master=92d399d086c9), phutil(head=master, ref.master=cb8cdccb1a50), sprint(head=master, ref.master=53f16c2f6fa0)
PHP message: #0 PhabricatorImageTransformer::getPreviewDimensions(PhabricatorFile, integer) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:112]
PHP message: #1 PhabricatorEmbedFileRemarkupRule::renderImageFile(PhabricatorFile, PhabricatorObjectHandle, array) called at [<phabricator>/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php:47]
PHP message: #2 PhabricatorEmbedFileRemarkupRule::renderObjectEmbed(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:114]
PHP message: #3 PhabricatorObjectRemarkupRule::renderObjectEmbedForAnyMedia(PhabricatorFile, PhabricatorObjectHandle, string) called at [<phabricator>/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php:368]
PHP message: #4 PhabricatorObjectRemarkupRule::didMarkupText() called at [<phutil>/src/markup/engine/PhutilRemarkupEngine.php:292]
PHP message: #5 PhutilRemarkupEngine::postprocessText(array) called at [<phabricator>/src/infrastructure/markup/PhabricatorMarkupEngine.php:138]
PHP message: #6 PhabricatorMarkupEngine::process() called at [<phabricator>/src/applications/conpherence/ConpherenceTransactionRenderer.php:59]
PHP message: #7 ConpherenceTransactionRenderer::renderTransactions(PhabricatorUser, ConpherenceThread, boolean, string) called at [<phabricator>/src/applications/conpherence/controller/ConpherenceViewController.php:70]
PHP message: #8 ConpherenceViewController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:218]
PHP message: #9 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:132]
PHP message: #10 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:19]
```
On the site it did nothing, but apparently it created this error in the logfiles. Later I downloaded the image file and then uploaded it into the drag&drop area from a file manager, which did not create such an error and successfully uploaded the file.