fix: 修复右键打印不识别改后缀的图片问题

[myk1343]

修复右键打印不识别改后缀的图片问题

Bug: https://pms.uniontech.com/bug-view-315823.html
Log: 修复右键打印不识别改后缀的图片问题

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在reader.jumpToImage(imagePtr->frame);之后添加了对reader.canRead()的检查，确保图像能够被读取。
• 添加了对图像格式自动检测和内容识别格式的设置，以处理可能出现的格式识别问题。

是否建议立即修改:

• 否，提交的代码已经实现了对图像加载失败的处理，并且通过自动检测和内容识别格式来提高图像加载的鲁棒性。这些改动是合理的，没有发现需要立即修改的问题。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: myk1343, pengfeixx

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[myk1343]

/forcemerge

[deepin-bot]

This pr force merged! (status: unstable)